Exotic Forests and Land Use
The Use of 2,4,5-T in Victoria (various)
Forest Commission Victoria Decisions (1974-79)
Pesticide Review Committee Minutes (1969-1977)
The Herbicide 2,4,5-T and its use in Forestry
The Contribution of Intensive Plantation Silviculture to Industrial Development in Australia and New Zealand
Tree Fern Removal - Strzelecki Ranges 1994-98.
Exotic Forests and Land Use
(This excellent article was first published in 1967 on a paper presented to the 39th ANZAAS Congress, Melbourne, January, 1967 and later published in Forestry Technical Papers No. 19 - Victoria Forests Commission).
The history of exotic forest and land use has passed through several phases during the past hundred or so years. Although Victoria was naturally well endowed with native forests, the introduction of exotic trees seems to have occurred within months of the first settlement. Early introductions were probably for reasons of sentiment, as abundant supplies of timber were available from the native forests, even though the timber characteristics of the local hardwoods were very different from the familiar softwoods of the northern hemisphere.
It was during the 1840's that the first plantings for protection appear to have been made, but it was not until the introduction of Pinus radiata D.Don by Baron von Mueller in 1859 that windbreak planting commenced in quantity. Pinus radiata was a very successful introduction from the first and during the 1860's and 1870's was planted extensively as shelterbelts in a wide range of climatic zones. Concurrently with this expansion a wider interest in other species developed, leading to the establishment of the Macedon Forest Nursery in 1872.
With the decline of the gold boom of the 1850's and the need to find employment for ex-miners, land settlement schemes expanded rapidly in the 1870's and 1880's. Large areas of highly productive forest throughout the medium to high rainfall areas of the State were released for settlement and it was during this period that the prime forest of the Otways and Gippsland regions was alienated; reducing the State's reserves of high quality forests to about half their former extent. Much of this country is now highly productive agricultural land but on large areas settlement has either failed or is a very doubtful economic proposition for both the owner and the community.
Alienation of forest areas was a very live issue and while only small, little more than token areas were reserved, it did plant the ideas of reforestation. For the first time it was realized that the "vast and inexhaustible" reserves were neither vast nor inexhaustible and a start was made by the State with the planting of a small area of P.radiata near the Macedon nursery in 1880. During the period 1880-1910 further projects were commenced at Mt. Macedon, Creswick and the You Yangs, representing high, medium and low rainfall areas. This period may be regarded as an experimental era; while the actual areas planted were small, techniques were evolved and over a hundred hardwood and softwood species of commercial value were tried in plantation formation.
Throughout these trials P.radiata was generally the most successful species. Its extensive use as a shelterbelt tree since about 1860 further confirmed its adaptability and suitability to a wide range of sites and was largely responsible for the fallacious belief that "it would grow anywhere." While it is a very versatile tree as regards site, it has definite limitations, particularly under conditions of excess or limited drainage, but the "grow anywhere" belief was carried to extremes and led to some rather unfortunate results.
B. PRE-WAR II PERIOD.
Planting of exotic forests began to expand in 1910, partly to provide for future timber requirements and partly to utilize land not suitable for agriculture. This may be regarded as the first conscious attempt at land use. Operations continued at varying levels and, may be divided into three main eras, witha few minor ones:-
1. Coastal sands 1910 - 1935.
2. Foothill Country 1925 - 1938.
3. Marginal farmlands 1930 - 1939.
1. Coastal Sands.
While much of the better quality forest in Victoria had been alienated by 1900-1910, the poor quality brown stringybark (Eucalyptus baxteri (Benth Maid. and Blak.)) forests on the sandy soils along the coast were of very limited forest value, and, judging by the absence of selection pressures, of little use for agriculture.
Following the acceptance of the "pines-will-grow-anywhere" belief, it was considered desirable in the interests of better land use, to convert these areas to softwood plantations; but however commendable the motive may have been, the results led to a most unfortunate phase of reforestation in Victoria.
Operations commenced at Frankston in 1910, French Island 1911, Wilson's Promontory about 1913, Port Campbell 1919, Anglesea 1923, and Mt. Difficult 1925. (Mt. Difficult, although not in a coastal area, is of the same soil type as the others and originates from the same era). Some 12,000 acres were cleared and planted but planting generally failed. Satisfactory areas of growth were very limited and scattered, so that consolidation was not practical. Planting generally ceased in the 1920's with minor work up to 1935, and except for a few hundred acres at Port Campbell, these plantations have now been utilized and the land disposed of to other interests. It is regrettable that despite the costly example of these failures, pressures still occur from time to time for major planting to be undertaken on similar soils in other parts of the State.
Numerous trials and investigations have been undertaken over the years in an
effort to determine the cause of failure. There is no one explantation to suit
all cases, but the commonest cause is either excess or inadequate drainage.
The older sands, particularly those on a gently undulating uplifted plain are
almost invariably unsatisfactory but younger soils developed on the slopes of
dissection lines and from recent geological activity are usually suitable. On
the older sands where inadequate drainage is the main cause of failure, it is
possible that deep ploughing or ripping (3 to 4 feet depth) with mole drainage
could be satisfactory. Application of phosphatic fertilisers has given good
responses on some types but the indicated frequency and rate of application
made the economics doubtful. Moreover, the response areas comprise only a minor
proportion of the total area and are usually dispersed through much larger areas
of unsuitable country.
Planting on coastal country has not ceased altogether; in fact, one of the largest current projects is on the sandy country of the south-west. Careful survey is necessary to define planting areas and it is only on soils developed on the Gambier Embayment and Recent period activity in the Dartmoor locality that any substantial areas of suitable country have so far been located. Soils derived on Pleistocene or older sands are usually unsatisfactory. In the south-west there is more than a million acres of sand country, but in the light of present knowledge only a small proportion of it is suitable for softwood reforestation.
2. Foothill Country.
By the mid 1920's it had become apparentt that the coastal sands were not suitable for P.radiata and while other species and techniques were tried during the following few years, activities were generally transferred to the foothill country of the central and north-eastern highlands.
Native forests around Ballarat suffered severely as a result of the demand for mining timbers and despite silvicultural treatment, recovery in some cases was slow. Conversion of some of these poorer areas to softwood commenced on a small scale in 1916, but most of it was undertaken in the 1925-1935 period. Generally the results have not been very successful, and no further extension of this class of planting is proposed for the present. However, investigations are in progress as it is estimated that some 30,000 acres of low quality native forest is available in the region and with its close proximity to the Ballarat, Geelong, and Melbourne markets it represents a potentially valuable area.
In the north-east of the State there is a very large area of forested country carrying faulty and defective timber of little or no commercial value. In 1927 a start was made at Bright and Myrtleford to convert some of this class of softwoods with a further project commencing at Beechworth in 1931. Within a planting unit there was no selection of site, so that some poor areas have been planted. Some were also too steep for subsequent operations.
The total area of foothill type forest carrying non-merchantable timber in the north-eastern highlands totals some millions of acres. Much of it is too poor and/or too steep for reforestation purposes but even excluding these areas the remainder still represents the largest potential for reforestation in the State. Up to 1939 only about 20,000 acres had been converted to softwood.
3. Abandoned Farmland.
The high quality forests of the Otways region were opened for settlement in the late 1870's but within about 50 years the forest authorities were resuming areas abandoned, or acquiring them at nominal prices. The opening up of the high country in the Otways and Strzeleckis from 1975 onwards for settlement represents one of the most unfortunate cases of wrong land use in the history of the State. Besides the loss of timber, the financial loss to the community and the wastage of human effort over two generations cannot be calculated, and only serves to emphasize once again that settlement of forested land needs to be carefully investigated.
Some of the land naturally reverted to forest but some 7,000 acres near Beech Forest have been replanted. A variety of softwoods was planted in the 1930-1938 period and now forms one of the most productive stands in the State. Several thousands of acres of bracken- and scrub-covered private property still exist and are potentially available. It is probably that with the exception of some very good farmland along the main Otways ridge most of the region will eventually revert to forest.
A similar position exists in the higher country of the Strzelecki Ranges where there is an estimated 200,000 acres of land which in retrospect it is apparent should not have been cleared. Much of this has been acquired by public and private interests, generally at token prices, and is or will be replanted with both softwoods and native hardwoods. Over the next 20 to 25 years this region will be one of the main centres of reforestation in the State.
While the three previous examples of land use and exotic trees represented the major part of the acreage planted up to World War II there are several other smaller and possibly more interesting cases of land use.
(a) Auriferous Areas. An aftermath of the gold mining era in Ballarat, Creswick and Castlemaine was the denuded and unproductive areas of worked-out diggings. Partly to put the land to better use and partly to hide an unpleasant sight, planting of such areas commenced in 1888 at Creswick and at Ballarat and Castlemaine in 1919. Under natural conditions the auriferous soils are too poor for satisfactory tree growth but when disturbed by mining operations a big improvement is often obtained. This is largely a reflection of internal soil drainage and root penetration; under natural conditions the soils are compacted with a relatively impervious B horizon underneath a shallow A horizon, but mining operations results in several feet of "loose" soils being created. Responses like this suggest that deep cultivation to 3 or 4 feet may give a big improvement in site where low quality is due to compacted soils and not inadequate soils depth.
When most of the mined land had been planted, activities extended to the surrounding low quality native forest. Generally these did not prove to be very satisfactory, so that further extension has been confined to the more favourable localities.
(b) Dredged gravels. During the 1890's and early 1900's gold dredging extended into the Ovens Valley and its tributaries. At the peak of operations more than 40 dredges operated in the valley destroying large acres of alluvial flats and leaving a churned up mass of course gravels.
An experimental planting of 80 acres of P.radiata at Bright in 1916 on dredge trailings was very successful, so that over the next ten years several hundred acres were planted. These areas are some of the best in the Bright group of plantations.
Areas dredged more recently are not so satisfactory. With improved techniques and processing, soils have been disturbed to much greater depths and too high a proportion of the finer particles have been washed out. On such areas tree growth has not been satisfactory and many are now being converted to pasture of a kind.
(c) Fire-killed areas. Following a succession of fires some thousands of acres of high quality hardwood forest in the upper Yarra-Latrobe-Acheron watersheds had over a period of years been reduced to open bracken fern. Planting of these with softwoods commenced at Narbethong in 1934 and Noojee 1935. Both areas were burnt in the 1939 fires and have been replanted. There are still many thousands of acres of similar country in small blocks throughout the above catchment areas, but because of their scattered nature and now that suitable techniques for large scale planting of native eucalypts have been evolved over the last 30 years they are being replanted with species native to the locality.
(d) Noxious Weed Control. During the 1920's some hundreds of acres in the Ovens Valley infested with St.Johns Wort were planted with softwoods. The stands gave good control on the planted area but of course had no effect on other areas.
C. POST-WAR PERIOD
Prior to World War II most of the planting in the State was undertaken by the Forests Commission with limited plantings by some other Government and semi-Government organisations. Private planting had been virtually confined to the activities of some afforestation companies in the extreme south-west of the State and to woodlot planting on farms. At the close of World War II, it was estimated that the total area of softwoods in Victoria was approximately 57,000 acres.
Immediately after the war planting was resumed by the Forests Commission, but sever reduction in Loan funds in 1951 meant that planting during the 1950's was virtually nil and was not resumed on a worth-while scale until 1961. Contrasted with this, private reforestation has increased markedly, so that at present its total area and annual planting rate exceeds that of the Forests Commission. Comparitive total area figures (as at 31/12/1966) are 89,700 acres for private plantations and 72,100 acres for Forests Commission areas.
The big increase in private plantings has been due mainly to activities of the A.P.M. Forests Pty Ltd., which since 1951 has been planting approximately 3,000 - 4,000 acres each year in Central Gippsland. Their present area (as at 31/12/66) is 49,200 acres. Other large private owners are Sapfor Ltd, 15,010 acres and Softwood Holdings Ltd. 13,150 acres.
The expansion of planting in the post-war years has seen the emergence of slightly different approaches by the government and private sectors as to what constitutes the lower limit of land suitable for planting. Government activity can potentially spread over most of the State, so giving a wide range of sites from which to choose whereas a private organisation is more concerned with forest resources close to its conversion or manufacturing centre. Consequently its choice of sites is more limited and it may be more economical to plant a poorer site close to its facilities than a better site one or two hundred miles away. This has led to private organisations planting some thousands of acres of sand country which the Government would be reluctant to consider at present.
Each locality needs to be considered seperately in the light of the organisation involved, its management objectives and economic policies. The interaction of these may be quite complex, so at this stage of development of the State it is not possible to indicate conclusively what would constitutute the lower limit of land use. . .
post - war private and public planting has been undertaken on similar classes of country. Whereas pre-war I the selection of planting sites in the main tended to be based on utilizing a certain class of country, for example, coastal sands or foothill country, and then to select suitable sites within this class; the approach in post-war years has been to select suitable sites without being unduly concerned with the particular class of country involved. The effect of this has been that the range of country planted has broadened considerably and now comprises the suitable sites of almost all the classes previously tried.
Without distinguishing between public and private operations, the main classes currently being used are:-
1. Younger coastal sands.
2. Unproductive native forest.
3. Abandoned and marginal farmlands.
1. Younger Coastal Sands.
Reference to activities on this type has already been made. In the immediate post-war years large areas were planted in the south-west between Portland and the State border and the main ares have now been planted or committed. Until techniques giving rise to satisfactory growth are evolved it is unlikely that any greater major use than that attained or planned could be anticipated. As far as the eastern Victorian sands are concerned preliminary surveys show that they are similar to the south-western and southern types but the much greater frequency of seasons of summer rainfall with its consequent higher humidity and risk of fungal infections (mainly Diploidea) emphasizes the need for caution before embarking on any major project.
2. Unproductive Foothill Forest.
This class is bsically the same as the class "Foothill Country" referred to earlier but the above term is used to distinguish the proposed planting areas from the productive and potentially productive foothill forest of medium to high quality. It comprises the lower quality areas and while theoretically these could in time be improved to form useful native forest the cost of rehabilitation, coupled with the relatively slow growth rate and long rotation, make them an uneconomic proposition.
The area available and suitable for softwoods has not been completely assessed. In general terms it is known to be some hundreds of thousands of acres throughout the medium to high rainfall areas of the State and will represent the main area of activity in the future.
3. Abandoned and Marginal Farmland.
Next to the "Unproductive Foothill Forest" class this represents the largest area available for reforestation. It is usually land which under natural conditions carried good quality forest and so was assumed to be good agricultural land but on which far a variety of reasons farming has not been very successful. Much of it is still only partly cleared.
The largest area is in the higher parts of the Strzelecki ranges. A gross area of 200,000 acres could be available and up to date approximately 130,000 acres have either reverted to the Crown or been purchased by public and private forest interests. Most of the land purchased has been acquired since World War II, initially at prices of $1-3 per acre but as the poorer farms have been acquired prices have risen to $10 to $15 per acre.
A similar but smaller region exists in the Otways. Land resumption commenced in the 1920's and some 30,000 acres have been acquired. Further extension is limited as it appears that only some 12,000 - 15,000 acres could be regarded as purchase possibilities.
Land resumptions have not been confined to these two areas but have been in progreess in most areas of the State where public or private reforestation has been undertaken. Surveys and reconnaissances have shown that large areas could still be acquired, so that the total area of marginal farmland potentially available is large, possibly as much as 100,000 acres. Most of it is in regions where the growing season is short, topography is too steep, or the soils are poor and impoverished. . .
Public reforestation since 1961 has been increased to an annual planting of 6,000 acres of softwood. The Commonwealth Government has announced a program of financial assistance to the States aimed at planting 65,000 acres of softwood each year, of which Victoria's share will be 15,000 acres. The present intention is that the project be continued for 40 years, i.e. approximately one rotation for P.radiata, so that 600,000 acres of land will be required.
In arriving at these figures it has been assumed that private interests throughout the Commonwealth will plant an average of 10,000 acres per year, even though annual plantings may fluctuate from year to year. It is probable that 6,000 acres of this total will be planted in Victoria, representing a total area of 240,000 acres over 40 years.
The proposed public and private program over the next 40 years, together with the 154,000 acres at present established, would give a total acreage of about one million acres of softwoods early next century. This is a large increase over the present area but it is necessary to keep it in perspective in relation to other land uses. It represents less than 2 percent of the total area and less than 6 percent of the total timber area in the State so that the overall impact on either will not be great. Some of the land to be planted will be alientated land but although the figures quoted earlier on the estimated area of abandoned and marginal land may appear to be large, they represent less than 1 percent of the total area of agricultural land in the State, while their contribution to production and revenue of the community as a whole is negligible.
Although pressures for planting land may increase in the future, softwood reforestation will by and large fill a gap in the present general pattern of land use. On the agricultural side, most of the productive land receives less than the optimum rainfall for softwoods, has an unsuitable soil type, or is in well improved farms where the initial purchase price and compound interest for 40 years would make reforestation uneconomic. From the forestry aspect productive or potentially productive stands on areas which can be economically rehabilitated will be retained as native forest. In between these two limits there is a large class comprising marginal farms, isolated blocks of timbered private property, and unproductive and uneconomic native forest. It is in this class of country that public and private softwood reforestation will generally be undertaken. It will lead to a much more rational land use and will eventually bring into highly profitable production about a million acres of land most of which is at present making a negligible contribution to the community.
The Forests (Wood Pulp Agreement) Act 1966. by L.B. Williams. Forestry Technical Papers.
This paper helps explains that after the 1939 bushfires there was a shortage of timber anticipated for the Maryvale Pulp Mill. 1936 Legislation guaranteed A.P.M. a supply of timber that would feed their newly made mill. The bushfires upset this supply arrangement and plans were drawn up some years later to plant forests on Crown Land and private land that would be used exclusively for the pulp mill. This led to the 1961 Wood Pulp Agreement Act and numerous variations since.
p36 "To help overcome this deficiency the 1966 Act lays down the procedure to be adopted for the leasing of Commission land to the company for the growing of trees for pulpwood. This should assist the company to develop an additional reserve of high grade pulpwood - particularly of Mt. Ash.
At the present time the Company leases from the Commission about 8700 acres of land in the eastern Strzelecki Ranges. terms of this lease require the company to establish trees in the plantable area contained therein over a period of 16 years. Since 1961 more than 200 acres have actually been established. It is anticipated that a further area of about 12000 acres will be made available in the Middle Creek and East Morwell river basins. This area abuts the current lease area and would in effect be an extension thereof..."
ADVANCES IN CONTROL OF WOODY WEEDS IN RADIATA PINE PLANTATIONS IN VICTORIA
D.W. Flinn and G.Minko 1980? Forests Commission Victoria
Sites converted from native eucalypt forests to plantations of radiata pine in Victoria are generally recolonised soon after planting by a wide range of herbaceous and woody plants. Of these, eucalypts and silver wattle exhibit rapid early growth rates and compete with radiata pine. At the highest density of woody weeds studies by Jack (1970), merchantable volume of a 51 year old stand of radiata pine had been depressed by 80%. Manual, mechanical and chemical methods have been used to control woody weeds in young plantations of radiata pine in Victoria. The method adopted has been largely based on available technology and economic and environmental factors. . .
PAST PRACTICES FOR WOODY WEED CONTROL
Until the early 1960’s, native forest was felled and broadcast burnt prior to planting of radiata pine. Repeated manual methods were needed to control woody weeds. Heaping and windrow burning then replaced broadcast burning allowing many sites to be ploughed before planting. This reduces the eucalypt component; temporarily controls many herbaceous weeds and provides a favourable micro-environment for establishing radiata pine seedlings.
In 1968 aerial application of 2,4,5-T approximately three years after planting was introduced to control silver wattle, followed by basal bark spraying or stem injection of the eucalypts with mixtures of 2,4,5-T and picloram (Flinn and Hopmans 1977). Since this control of eucalypts is labour-intensive, ploughing significantly reduced the total cost of woody weed control. Aerial application of 2,4,5-T has not been made by the FCV since 1977, and there has been increasing pressure on all 2,4,5-T based herbicides including those commonly used for stem injection. Since new plantations of radiata pine are being established by the FCV at about 2000 ha per year on sites cleared of native forest, and as the cost of hand slashing woody weeds can be prohibitive, there was an urgent need to find alternatives to 2,4,5-T . . .”
EVALUATION OF HERBICIDES FOR STEM INJECTION OF WOODY WEEDS IN YOUNG RADIATA PINE PLANTATIONS. G. Minko and D.W.Flinn 1980
“Until recently, the Forests Commission Victoria has used a combination of aerial spraying with 2,4,5-T, followed by stem injection with Tordon 105 (Picloram + 2,4,5-T) to control those woody weeds early in the rotation (Flinn and Hopmans 1977). Alternative herbicides have been investigated for broadscale application following restrictions placed upon the use of 2,4,5-T in Victoria and elsewhere in the late 1970’s. (Flinn and Minko 1980, 1981, Flinn et al. 1980). . .
“ PESTICIDES IN THE FOREST ENVIRONMENT. USE OF 2,4,5-T FOR CONTROL OF WOODY WEEDS IN PINUS RADIATA PLANTATIONS IN VICTORIA. By D.W. Flinn and P. Hopmans.
“. . . The application method is dictated by the density and size of the weeds. Basal bark spraying and stem injection are used where weed density is low and an aerial application at 1.1kg/ha 2,4,5-T where weeds are denser . . . Studies have demonstrated that 2,4,5-T is degraded in the forest environment, principally by photodecomposition and soil microorganisms, to harmless end products. Less is known about the breakdown of TCDD. . . Dense scrub growth often develops following conversion of native eucalypt forests to Pinus Radiata D Don plantations in Victoria. This scrub, especially eucalypts and wattles (eg Acacia dealbata Link.) competes strongly with the young pines and substantially reduces yields (Jack 1970) . . . Application is at the rate of 1.1 kg 2,4,5-T in 50 l dieseline/ha during winter . . . Since 1968 over 16,000 ha have been successfully treated . . . Although the degradation of TCDD has not been studied in detail and hence breakdown pathways and products have not been characterized . . . Recent studies indicate that TCDD is subject to photodecomposition (and presumably microbiological breakdown) and is very immobile in soils. Rates of decomposition are slow compared with 2,4,5-T. Animals excrete around 30% of TCDD immediately and high percentage of the balance within a few days. . .”
BROADSCALE FOREST USE OF HERBICIDES IN VICTORIA 13/6/03
BY J.B.JACK. FORESTS COMMISSION - VICTORIA
Paper presented to section K, A.N.Z.A.A.S. 40th Congress - Christchurch, 24-31 January, 1968.
p2 “Screening tests for suitable chemicals have been carried out since the early 1950’s. The chemical 2,4,5-T (2,4,5-Trichlorphenoxyacetic acid) gave excellent control of Acacia dealbata Link. as well as showing early promise in the control of eucalypt coppice. Later trials have confirmed the suitability of 2,4,5-T for certain situations and its limited application for growth control in plantations. Tordon (4-amino-3,5,6 trichloropicolinic acid) now appears as the most promising chemical in the woody growth control field.
p 3 APPLICATION TECHNIQUE
High volume foliar applications have generally been impractical in Victorian plantations because spraying equipment cannot move through the rows, even though technically they have proved equal if not superior to misting or injection techniques. Foliar applications by back-pack misters have given good control in small trials but in larger scale use the results have been poor . . .
Weather conditions can affect the results of spray operations. Aerial spraying of forest stands in Victoria with 2,4,5-T ester in oil or water has seldom resulted in more than 50% of the spray output being recorded on the spray area in droplets larger than 100 microns. When wind speeds of >5 m.p.h were recorded <30% of the spray reached the target. In contract to this 90% of aerially applied 2,4,5-T invert reached the target in winds of 8 to 11 m.p.h. The frequency of adiabatic winds in forest areas and the difficulty of flying close to the canopy make forest aerial spraying more hazardous than the usual agricultural operation both from the point of view of the pilot and the successful application of the herbicide to the target area.”
12/2/74: File Number 73/111. Chemical (Tordon herbicide). Spillage at Sherbrooke Falls. Commission Decision 74/6/16. Arrangements to be made for removal of unsafe dead trees. Advisory Committe to be informed.
11/3/74: File Number 74/414. Purchase of 2,4,5-T for Aerial Spraying Operations. Commission Decision 74/11/10. Approved recommendations submitted by Chief, Division of Forest Operations on 18/3/74.
12/3/74: File Number 73/2452. Zinc Spraying 1973/74. Commission Decision 74/10/20. Tender of A.G. Airwork Pty Ltd viz $2.10 per acre accepted.
6/6/74: File Number 74/200. Aerial Spraying of Wattle Areas 1974. Commission Decision 74/21/16. Recommend to Minister purchase ex Nufarm Chemicals Pty Ltd of 770 gallons of 2,4,5-T Technical Butyl Ester at $1.985 per lb (total cost $20,174) in accordance with company's quotation dated 23/5/74. MINISTERIAL APPROVAL 6/6/74.
20/11/74: File Number 74/1644. Aerial Dessicant Spray Operations 1974/75. Commission Decision 74/45/11. Quotation of Nufarm Chemicals Pty Ltd viz $1,623.60 accepted for supply of 60 gallons of technical buytl ester 2,4,5-T on accordance with company's letter dated 29/10/74.
?: File Number 74/2407. Zinc Sulphate - Aerial Spraying Rennick FD. Commission Decision 75/9/21. Tender of Western Aerial Crop Spraying and Spreading Pty Ltd viz $2.90 per ha accepted for spraying to specification with zinc sulphate 600 ha +- 20%.
13/3/75: File Number 74/414. Purchase of 2,4,5-T for aerial spraying operations - 1974. Commission Decision 75/10/14. Recommend to Minister purchase ex Nufarm Chemicals Pty Ltd of 2500 litres of 2,4,5-T to specifications at $2.10 per lb ($4.63 per kg) at a total cost of $15,047.50 with an option of purchase up to 4000 litres at same unit rate. MINISTERIAL APPROVAL 13/3/75.
26/3/76: File Number 76/412. Zinc Spraying 1976 Rennick State Forest. Commission Decision 76/13/5. Approved recommendation submitted by Chief Silvicultural Office on 26/3/76.
10/5/76: File Number: 74/1644: Aerial Desiccant Spray Operations 1974/75. Commission Decision 79/19/34. Approved recommendation submitted by Chief Division of forest operation on 10/5/76.
12/8/76: File No's 76/1524. Purchase of Herbicides Yarram Forest District. Commission Decision 76/32/23. Recommend to Acting Minister purchase ex Ciba-Geigy Aust Ltd of 156 x 20 Litres Weedazol TL Plus at $1.90 per litre (less 6%), 163 x 20 L Gesaprim 500 FW at $3.22 per litre as per State Tender Board contract and 65 litres of Plus 50 Surfactant at $1.04 per litre. Total Cost $16,137.12.
3/5/77: File Number 74/414. Purchase of 2,4,5-T for Aerial Spraying Operations 1974. Commission Decision 77/18/15. Recommend to Minister purchase ex Lane Ltd of 2440 litres of 2,4,5-T butyl ester (80% w/v) at $6.25 per litre as per company's quotation dated 2/5/77 - Total cost 15,250.
7/6/77: File Number 77/457. Aerial Spraying Wattle Control 1977 - Commission Decision 77/23/4. Tenders accepted for wattle spraying in accordance with schedule recommended by Silvicultural Officer B.T. Evans on 1/6/77.
19/7/77: File Number 77/457. Aerial Spraying - Wattle Control 1977. Commission Decision 77/29/11. Quotation dated 21/6/77 from Super Spread Aviation (Australia Ltd) viz $175 per hour working time and $95 per hour ferry time accepted for spraying to specification for wattle control on 300 ha +- of pine plantation in Myrtleford Forest District.
5/7/77: File No's 76/1524. Purchase of Herbicides Yarram Forest District. Commission Decision 77/27/8. Recommend to Acting Minister purchase ex Ciba-Geigy Aust Ltd of 201 x 20L Weedazol TL Plus at $1.50 per litre, 320 x 20 L Gesaprim Flowable at $3.40 per litre and 3 x 20 litres plus at $1.27 litre as per Company's quotation dated 17/6/77. Total cost $27,866.20
3/8/77: File Number 76/143. Plantation Establishment and Tending Yarram. Commission Decision 77/31/18. Tender of Skyfarmers Pty Ltd Vic $123.50 per hour flying time and $93.50 per hour ferry time for Cessna Agwagon accepted for spraying 920ha +- 20% of softwood plantation for grass control in Yarram Forest District.
17/1/78: File Number 75/2534. Plantation Establishment and Tending - Heywood F.D. Commission Decision 78/3/15: Approved purchase of ex Phosphate Co-op Australia Ltd of 120 tonnes granulated superphosphate in woven bags at a total cost of $7231.20.
17/1/78: File No: 77/1524. Aerial Fertilsing with Super Phosphate. Commission Decision 78/7/34: Approved recommendations submitted by Silvicultural Officer on 13/278.
31/1/78: File Number 77/1524. Aerial Fertilising with super phosphate. Commission Decision 78/5/8. (a) Recommend to Minister purchase ex The Phosphate Co-op of Australia Ltd of 933 tonnes of granulated super phospahte at $50 nett per tonne and 152 tonnes of granulated super potash 5 & l at $63.71 net per tonne. Total cost $56,333.91. (b) Invite quotations from known aerial contractors for transport, storage and aerial application of fertiliser on 1391 +- of plantation.
17/5/78: File Number 77/2456. Replanting Pine Plantations burnt at Creswick during February 1977 - Creswick FD. Commission Decision 78/19/13. Approved purchase ex Ciba-Geigy Australia Ltd of 480 litres of "Roundup" at $14.90 per litre.
?/5/78: File Number 74/414. Purchase of 2,4,5-T for Aerial Spraying Operation 1974. Commission Decision 78/20/12. Recommend to Minister purcahse ex Nufarm Chemicals Pty Ltd of 1800 litres 2,4,5-T as butylester (80% w/v 2,4,5-T) at $6.72 per litre in 20 litre drums. Total cost $11,196.
23/5/78: File Number 78/491. Aerial Spraying - Wattle Control 1978. Commission Decision 78/20/11. Approved recommendation submitted by Silvicultural Office on 10/5/78 as amended and initiated by the Chief Division of Forest Operations.
26/7/78: File No's 76/1524-76/143. Purchase of Herbicides Yarram District. Commission Decision 78/29/25. Approved purchase 26/7/78. (a) ex Nufarm Chemicals Pty Ltd of 87 x 20 litres of Amitrole T at $1.59 per litre as per State Tender Board contract and 2 x 20 litres surfactant at $1.24 per litre. (b) Ex Ciba-Geigy Australia Ltd of 152 x 20 litres of Flowable Gesaprim (Atrazine) at $2.45 per litre as per company's quotation of 6/7/78.
1/8/78: File No 75/550. Purchase of Hi-Ball and Chain for Machine Clearing. Commission Decision 78/30/10. Approved purchase. Ex Falkiner Chains Pty Ltd of four 28 metre lengths of 2 inch stud link chain, "U2" quality at a total cost of $5,840.00 and seven only Bolt Type Joining Shackles at a total cost of $120 each, in accordance with company's offers dates 11 July 1978 and 18 July 1978.
4/10/78: File No 75/2575. Plantation Establishment and Tending-Myrtleford FD. Commission Decision 78/39/11: Approved spraying for grass control on 150 hectares +- of softwood plantation in Myrtleford Forest District in accordance with programme detailed in letter dated 19/9/78 to Pesticide Review Committee.
25/1/89: File No's 77/1524-78/2141. Aerial Fertilising with Super Phosphate. Commission Decision 79/4/8: Recommend to Minister purchase of the PhosphateCo-operative Company of Australian Ltd of 1023 tonnes of granulated super phosphate at $51.40 net per tonne and 162 tonnes of granulated super potash 5 at $65.04 net per tonne - estimated total cost $63, 118.68.
28/2/79: File No: 77/1524. Aerial Fertilsing with Super Phosphate. Commission Decision 79/8/27: Recommend to Minister for spreading fertiliser to specifications on softwood plantations as follows: With Super Spread Aviation (Australia) Pty Ltd of 160 tonnes at $19.60 per tonne at Toolangi, 223 tonnes at $29 per tonne at Alexandra, 206 tonnes at $23.50 per tonne at Marysville, 162 tonnes at $26.90 per tonne at Mirboo and 202 tonnes at $27.05 per tonne at Erica and with Western Aerial of 207 tonnes at $17.19 per tonne at Daylesford and 25 tonnes at $19.50 per tonne at Ballarat.
7/3/79: File Number 75/2534. Plantation Establishment and Tending - Heywood F.D. Commission Decision 79/9/19: Approved purchase of ex Phosphate Co-op Australia Ltd of 100 tonnes superphosphate in woven bags at a total cost of $5883.
12/4/79: File No: 77/1524. Aerial Fertilsing with Super Phosphate. Commission Decision 79/14/15: Approved recommendations submitted by Chief Silvicultural Officer.
MINUTES OF THE TWENTY SECOND MEETING OF THE PESTICIDES REVIEW COMMITTEE 22/11/68.
31 Letter received from Forests Commission (maps enclosed) advising of spraying program at Brittania Creek, Fitzpatrick Road, Ada River, Dowey’s Spur and Learmouth Creek Road.
Decision 22.11.68. To notify Forests Commission that the Committee approved of the spray program and that there could be representatives of interested Departments on site during the spraying. Copy of Forests Commission letter to be circulated to members.
MINUTES OF THE TWENTY THIRD MEETING OF THE PESTICIDES REVIEW COMMITTEE 7/2/69.
Forests Commission Aerial Spraying. Letter dated 23rd December received from Forests Commission requesting extension of area to be sprayed. Amalgamated Chemicals to supply ‘Dibrom’ as comparison to Malathion. Area to be sprayed 100 acres.
MINUTES OF THE THIRTY FOURTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 10/4/70.
Decision 10/4/70. To notify that the Committee has no objection to the conduct of the trials as indicated.
(5) Forests Commission, in co-operation with Dow Chemicals (Aust) Ltd; Woady Yallock Creek near Scarsdale.
Decision 10/4/70. To notify the Forests Commission that the Committee has no objection to the conduct of the trials as indicated, but that the Forests Commission should notify the Committee of results of the trial.
MINUTES OF THE THIRTY FIFTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 15/5/70.
52. Dangers of 2,4,5-T - A letter to the Secretary, Premiers Department, from the Consul-General of the USA, underlining the dangers of the weed killing chemical 2,4,5-T was forwarded to this committee. (Also mentioned in 36th and 37th meeting).
MINUTES OF THE FORTIETH MEETING OF THE PESTICIDES REVIEW COMMITTEE 6/11/70.
ITEM 3: (a) Letter received from Forests Commission, Victoria, dated 29th October, advising the proposed desication of scrub land preparatory to the rehabilitation of former forested land back to productive forest. The chemical to be used is 2,4,5-T.
MINUTES OF THE FORTY FIRST MEETING OF THE PESTICIDES REVIEW COMMITTEE 11/12/70.
31 Aerial Spraying by Forests Commission The Chairman advised the meeting that after discussion with Mr McKenzie he had rung Dr Moulds concerning the area to be sprayed. It was thought that it might be too close to the water take-off at Brittania Creek. Dr MacKenzie advised that he had visited the area to be sprayed. He said that it would not be necessary to take water samples as the water take off was more than a mile away. Mr Parsons queried whether the dioxin content of the Australian product of 2,4,5-T was as stong as overseas operations. It was advised that there are six companies manufacturing 2,4,5-T in Australia and it was decided to write to each to ascertain the strength used in their products.
31 Letter dates 30th Nov received from the Forests Commission advising of the proposed spraying of 15000 acres plus, for the control of phasmatid insects. The chemical compound to be used is Maldison.
MINUTES OF THE FORTY THIRD MEETING OF THE PESTICIDES REVIEW COMMITTEE 5/3/71.
31 (b) Manufacturers of 2,4,5-T in Australia and the dioxin strength compared with overseas manufacture. Information was tabled which indicated that only two companies now make the compound in Australia. On the information supplied the dioxin content was shown to be less than 1ppm. and the committee felt that no further problem from this angle existing with the use of 2,4,5-T.
MINUTES OF THE FORTY FIFTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 14/5/71.
31 D (c) Forests Commission. Aerial spraying for control of weeds in young pine plantations. Letter received 13th May.
MINUTES OF THE FORTY SIXTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 18/6/71.
(c) Forests Commission Aerial spraying for control of weeds in young pine plantations. Letter received 13th May.
Decision 14.5.71. To advise the Forests Commission that the submission will be considered at the next meeting. A further letter dated 3rd June, concerning an area near Gellibrand, was received. This was added to the area already notified. Mr O’Brien advised that the Agriculture Department laboratories would be doing some collaboration analytical work on the scheme. Mr Dunk advised that the State Rivers and Water Supply Commission would prefer some form of control on the Tarra Valley area as the Yarram Water Supply comes from this area. 18.6.71
(a) To advise the Forests Commission that the Committee has no objection to the conduct of the spraying operation with the exception of the Tarra Valley from which the Yarram town water supply is drawn.
(b) The Committee would need to be convinced that spraying the Tarra Valley would be safe. Evidence of this point should be available from analytical data in other areas.
(c) To point out that because the compound concerned has been given adverse publicity recently more than usual attention should be taken to ensure that spray drift does not contaminate any waterways or storages.
(d) To suggest to the Commission that the applicator must have a permit from the Agriculture Department to use hormone sprays from the air.
(d) APM Forests Pty Ltd Letter received from APM dated 11th June outlining a spraying program similar to that proposed by the Forests Commission and also using 2,4,5-T. During discussions it was agreed that no catchment area or water supply would be affected.
Decision 18.6.71 (a) To advise APM that the Committee has no objection to the spraying operation as outlined. (b) To bring to the notice of APM that the applicator will require a permit from the Agriculture Department to use hormone spray from the air. (c) To point out that because this compound has been given adverse publicity recently, more than usual attention should be taken to ensure that spray drift does not contaminate any waterways or storage.
MINUTES OF THE FIFTIETH MEETING OF THE PESTICIDES REVIEW COMMITTEE 15/10/71.
Letter dated 13th October received from Forests Commission advising the proposed desiccation of scrubland preparntory to the rehabilitation of former forested land back to productive forest. The chemical to be used is 2,4,5-T. Decision 15.10.71
(1) To advise the commission that the committee has no objection to the spraying of the areas designated.
(2) To request that on future occasions directions in the contractor not to spray adjacent to streams for at least one chain, be included in the specifications to the contract.
(3) To request that water samples be taken before and after spraying and then after the first rain for analysis by the Department of Agriculture Laboratories.
(4) To ask if the commission has obtained data from previous operations and if so the committee would be pleased to have a look at the results.
MINUTES OF THE FIFTY SECOND MEETING OF THE PESTICIDES REVIEW COMMITTEE 17/12/72.
31 (c) Forests Commission - Letter dated 6th December received from Forests Commission advising that the Commission intended spraying certain areas of forest against the stick insect phasmatid.
MINUTES OF THE FIFTY THIRD MEETING OF THE PESTICIDES REVIEW COMMITTEE 18/2/72.
Item 31 (c) Forests Commission - Reports dated 17/12/71 and 7/1/72 received on results of spraying programs carried out during the 1971 spraying season.
Decision - 18.2.72 To thank the Forests Commission for the reports on testing programs.
MINUTES OF THE FIFTY EIGHTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 1/9/72.
31 (c) Forest Commission Spraying Programme Letter dated 12th July received from Forest Commission advising the intention to carry out aerial spraying of various plantations of approximately 8000 acres located on enclosed schedule.
Decision: 21/7/72: (a) If the Committee has not already received a report from the Forests Commission about the efficiency of foam barriers, one should be asked for.
MINUTES OF THE EIGHTY NINTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 24/11/72.
No 31 (c) APM Latter dated 22 Sep received from APM concerning Dioxin produced by burning 2,4,5-T and including an article by Jane Cameron, University of British Columbia.
MINUTES OF THE NINETIETH MEETING OF THE PESTICIDES REVIEW COMMITTEE 24/11/72.
Letter dated 13th Nov, received from Forests Commission Victoria advising of the Commission’s proposed control measures against the plague proportions of the phasmatid Didymuria violesceus in areas of the Upper Yarra and Neerim Forest District No 31
(c) APM Letter dated 22 Sep received from APM concerning Dioxin produced by burning 2,4,5-T and including an article by Jane Cameron, University of British Columbia.
MINUTES OF THE NINETY FIRST MEETING OF THE PESTICIDES REVIEW COMMITTEE 16/2/73.
No 31 (a) Letter from Forests Commission dated 13 Dec received advising of spraying for control of phasmatids. The area to be sprayed is adjacent to the water catchment for the Warburton Water Supply. Letter received from MMBW dated 13th Dec confirming information provided by Forests Commission.
No 31 (c) APM Latter dated 22 Sep received from APM concerning Dioxin produced by burning 2,4,5-T and including an article by Jane Cameron, University of British Columbia.
MINUTES OF THE NINETY SECOND MEETING OF THE PESTICIDES REVIEW COMMITTEE 23/3/73.
31 (a) Letter of 16th March 73, received from the Forests Commission advising that it was proposed to spray a defoliant on scrub and blackberries at Turtons Creek, Mirboo Forest District so that the area of approximately 100 acres could be reforested.
31 (c) APM Forests Pty Ltd. Letter dated 22nd September received from APM concerning Dioxin produced by burning 2,4,5-T and including an article by Jane Cameron, Uni of British Columbia.
Decision: 20/10/72: To reply to APM Forests Pty Ltd advising that this committee is not the body to organise a symposium but that we would be very happy to see the results of such a gathering. Letter dated 13th Nov received from Mr Parsons commenting on paper by Jane Cameron student in Political Science.
Decision: 24/11/72. Mr Parsons to draft reply to APM on this matter. Secretary to provide Mr Parsons with a copy of the information involved. Letter Dated 29th Nov 72, and 11th Dec 72 received from Mr J Hall referring to the matters listed above.
MINUTES OF THE NINETY THIRD MEETING OF THE PESTICIDES REVIEW COMMITTEE 12/4/73.
31 (c) APM Forests Pty ltd. Correspondence from Mr Hall APM wanting a symposium on 1080 - also letter from APM outlining maps where 1080 will be used in April May under direction of Lands Department.
MINUTES OF THE NINETY FOURTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 1/6/73.
31 (c) APM Forest Pty Ltd. (a) letter dated 14th May, received from APM concerning the use of Propazine and 2,4,5-T in various areas in Gippsland, and enclosing a map of the area.
(b) Forests Commission - Letter dated 18th May received from the Forests Commission enclosing maps of the areas in which it is proposed to aerial spray 9000 acres of pine plantation with 2,4,5-T. Decision: To approve of the proposal subject to:- (a) That sampling of the stream be carried out.
(b) That they advise any town authority where the water supply might be affected and also to advise the State Rivers and Water Supply Commission similarly.
MINUTES OF THE NINETY FIFTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 29/6/73.
31 (1) Letter dated 14th May received from APM concerning the use of Propazine and 2,4,5-T in various areas in Gippsland, and enclosing a map showing the area involved.
Decision: 1/6/73 To write and advise that more information is needed and that the committee would be prepared to meet them on a subcommittee basis if approval is required quickly. Advise that they have not advised what is intended to control - what amount of residue would be involved - the proximity to streams - how material will be applied and when.
Letter dated 15th June received from APM Forests Pty Ltd setting out the programme and specification to be used in this exercise.
MINUTES OF THE NINETY SIXTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 3/8/73.
31C Letter dated 25th July 73, received from APM advising of the proposed use of Simazine, Amitrol and 2,4,5-T on 220 acres of recently planted pines in the Flynn Creek Tree Farm at Rosedale.
MINUTES OF THE ONE HUNDRETH MEETING OF THE PESTICIDES REVIEW COMMITTEE 1/2/74.
Letter from Forests Commission 20th Nov to spray plague proportions of phasmatids in the Upper Yarra and Neerim forest districts (catchment areas).
MINUTES OF THE ONE HUNDRETH AND FIRST MEETING OF THE PESTICIDES REVIEW COMMITTEE 29/3/74.
16th Feb letter dated from APM - 1080 to be used in Gippsland Tree Farms - May 74.
MINUTES OF THE ONE HUNDRETH AND SECOND MEETING OF THE PESTICIDES REVIEW COMMITTEE 10/5/74.
(1) Letter dated 29th March received from APM Forests Pty Ltd advising the firms intension to spray 890 hectares of new ploughed ground with 80% w/w Simazine to prevent germination of grasses, cape weed and silver wattle. No Objection.
MINUTES OF THE ONE HUNDRETH AND THIRD MEETING OF THE PESTICIDES REVIEW COMMITTEE 21/6/74.
(1) Letter dated 5th June, 1974 received from the Forests Commission advising that the Commission intends to aerial spray about 7,600 acres in various areas, with the defoliant 2,4,5-T. Mr McKimm advised that this was a tentative application and the spraying would depend on the receipt of an order for 1000 gallons of 2,4,5-T in July and must be done by the first week in August or not at all. He also said that further tests were being made concerning at what stage peaks of run-off into rivers from the forests occurs. Peaks occur at two different times, (a) at time of spraying (peaks last for 2-3 hours), (b) following rain in the sprayed area (peaks last for 8-10 hours). The Chairman said that the committee would be interested to see the results of the report to be made in conjunction with Agriculture Dept Laboratories.
Decision. To advise the Forests Commission that the committee has no objection to the spraying as set out.
MINUTES OF THE ONE HUNDRETH AND SEVENTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 25/10/74.
(1) (a) Letter dated 24th September received from APM Forests Pty Ltd advising the intension to spray 275 hectares of farmland to control ragwort. (b) Forests Commission - letter received dated 17th October advising of proposed spraying of areas, 1. Upper Yarra district, 2. Nowa Nowa district.
MINUTES OF THE ONE HUNDRETH AND EIGHTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 29/11/74.
(1) Letter dated 7th November received from Forests Commission advising of proposed spraying of areas in Upper Yarra (New Turkey), Neerim (Carters Creek) and Erica (Western Tyers A,B & C) for control of plague proportions of phasmatids, during Jan 75. Total area to be sprayed 1070 hectares (2640 acres).
MINUTES OF THE ONE HUNDRETH AND NINTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 21/2/75.
Item 93 Use of 1080 for Vermin Control . . . Letter dated 3 January received from APM Forests Pty Ltd advising proposed use of 1080 for vermin control in various areas during May, 1975.
Decision 21.2.75 Mr Wharton to advise APM of the procedure necessary before controlling vermin with 1080 and that a permit must be obtained from Fisheries and Wildlife before undertaking such work.
(d) Tarra Valley National Park - Blackberry Spraying. Letter received from Mr O’Brien from the Department of National Parks requesting authority to spray blackberries along the Tarra River a portion of the area to be sprayed being a proclaimed water catchment area. It was stated that various restrictions would be enforced against spraying close to the stream and the cleaning of equipment used to spray. 2,4,5-T is the material to be used at a dilution of 1:600.
MINUTES OF THE ONE HUNDRETH AND TENTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 11/4/75.
(1) APM FORESTS Pty Ltd (a) a letter dated 5th March 1975, received from APM advising that the company would be spraying specific areas with 2,4,5-T to control Blackberry and Brambles.
Decision 11.4.75 (i) To note receipt of the letter and the action taken (ii) To advise APM that the Committee regrets that the spraying was done prior to it receiving notification and would request that this be done in future.
(b) Letter dates 6th March received from Forests Commission, together with reports of studies carried out by the Commission on the safe control of Didymuria violescens.
MINUTES OF THE ONE HUNDRETH AND TWELFTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 27/6/75.
(A) (1) Letter dated 21st and 23rd April received from APM Forests Pty Ltd, advising plans for the use of 2,4,5-T to control noxious weeds in various areas of Budgeree, Bulga and Callignee. The Secretary advised Mr Pollock that approval could not be given until all information had been considered.
Mr Pollock has contacted the Secretary by telephone and said that in these instances the Coy. Had no option but to spray because a direction from the Vermin and Noxious Weeds Destruction Board had been received which required the spraying of blackberries and brambles by a certain time. Mr Jack said that this was a regular operation which was carried out each year and could conceivably be planned ahead and the committee notified.
Dr Christophers said what should happen now was for APM to make a general application for control of noxious weeds and having regard to the hazards which might be entailed, notify the committee when the project will be carried out.
Decision - To accept offer from Mr Jack that he would discuss the matter, along these lines, with Mr Hall of APM.
(b) Forests Commission. Letter dated 17th April received from the Forests Commission advising of proposed aerial spraying with 2,4,5-T during the winter.
Decision 9.5.75 - (1) To advise the Forests Commission that the Committee has no objection to the conduct of the spraying program as set out.
(2) That for future occasions when notifications are received from the Secretary, send a copy of correspondance, maps, etc., to Mr Bill for checking which will then eliminate the need for the full committee to look closely at the proposition.
(9B) (b) Use of 1080 for vermin control. Letter dated 29th April received from APM Forests Pty Ltd advising the proposed use of 1080 to control vermin under Health Department Permits held by the company. The areas to be treated are in the Parishes of Narrang, Windoo, Coolungoolun and Walla Wullock.
MINUTES OF THE ONE HUNDRETH AND THIRTEENTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 25/7/75.
Item 1 APM Forests Pty Ltd Mr Jack reported that he had spoken to the manager of APM and Mr Pollock had not included in his notification, the precautions to be observed by spraying teams, although there has been a verbal acceptance of the suggestions made. Information was handed in at the meeting from APM Pty Ltd, inclcuding maps, appropriate areas, broad locations and the chemicals and rates of use.
Decision (1) That Mr Jack, Mr Pearce and Mr Bill form a sub-committee to consider the information provided. (2) To agree that the program as set out by APM be accepted. Mr Jack advised that in his opinion APM’s submission is a bit weak on the ‘precautions’ aspect. He suggests that the ‘specification for Aerial Spraying’ should be expanded to require:- 1) Notification, of neighbours and water users, of the intended operation. 2) Avoidance of spraying over running streams or dams. 3) That the chemical meets a specified tolerance and perhaps in the case of 2,4,5-T a purity level eg dioxin 0.5ppm.
In regard to the purity level of 2,4,5-T, Mr Jack said he had recommended a safe tolerance because dioxin could be present in this material especially in old stocks which could be unstable. It was advised that it was a general requirement for 2,4,5-T, produced in Australia, to be free from dioxin. Mr O’Brien offered to check this out with Mr Snelson in Canberra. Water Sampling, it was agreed, did very little good because it took only a short time to dissipate the chemical and in any case it was considered that the material prevented no great hazard at its registered strength . . .
Decision (a) To advise APM Forests and Lands that precautions should be observed as follows:- (1) Neighbours and water users should be notified of the intended operation. (2) Spraying over running streams and dams must be avoided. (b) That the Fisheries and Wildlife Branch check on the use of 1080 for the control of Black Faced Wallabies in pine plantations.
MINUTES OF THE ONE HUNDRETH AND FOURTEENTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 19/9/75.
(1) APM Forests Pty Ltd, letter dated 6th August 1975, received, advising further areas in the Gippsland area proposed for spraying with 2,4,5-T. Letter dated 12th Sep, 1975 received in reply to ours of 4th September advising of the action taken by APM when spraying or baiting is to be carried out. Mr Bill advised members that the matter of aerial spraying and baiting by APM was discussed by the Water Commission and that the Commission was in favour of the Latrobe Valley Water and Sewerage Board and Waters Trust concerned, being notified when these were to take place Although it was considered that there was no great hazard involved it would be a good Public Relations exercise. It could be assumed that APM would be aware of the Public Relations angle.
MINUTES OF THE ONE HUNDRETH AND FIFTEENTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 31/10/75.
(1) APM Forests Pty Ltd - Applications from approval to spray pine plantations have been received from APM from time to time and now a yearly program has been presented and agreed to by the Committee. The matter of notification of neighbours etc has been considered and Mr Bill has drafted a circular letter which could be used to warn those interested when spraying has to take place. It was pointed out that it would be better if the organization doing the spraying was to notify water authorities and diverters rather than have the water commission do this.
(3) Vermin and Noxious Weeds Destruction Board sprayingh of ragwort on Mt. Tassie area. Letter received from V&NWDB advising of the intention to spray 100 acres of ragwort in the Mt.Tassie area. Sparying to be carried out by aircraft.
MINUTES OF THE ONE HUNDRETH AND SIXTEENTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 28/11/75.
(1) APM Forests Pty Ltd, Forests Commission . . . Pine plantation spraying for the control of unwanted growths of wattle etc and attack by wildlife has been discussed at a number of meetings. A yearly program has been put forward by APM for its requirements so that delay in operations, will be reduced to a minimum . . .
(2) Forests Commission. A letter of notification of the intention to spray was tabled by Mr Jack . . . for control of phasmatid insects in various areas of forest which were threatened. The area this year was reduced to 200 acres approximately. No objection from Committee.
MINUTES OF THE ONE HUNDRETH AND SEVENTEENTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 20/2/76.
APM letter received from APM dated 28th Jan advising their intention to spray with 2,4,5-T noxious weeds in parts of the Parished of Callignee and Budgeree which were not advised in the letter of 26th June 1975 (Received and Approved).
Letter dated 13th Feb 76 was received from their Gippsland Manager of APM Forests advising of their proposal to spray certain areas in the Parishes of Allambee, Narrang, Nindoo, Glencoe South, Coolunggoolun and Holey Plains.
MINUTES OF THE ONE HUNDRETH AND EIGHTEENTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 9/4/76.
(4) Letters dated 13th and 20th Feb, 10th and 22nd and 31st March from APM Forests advising of their intention to spray certain areas in the Parishes of Allambee, Narrang, Nindoo, Glencoe South, Coolungoolum, Holey Plains, Yinnar, Jeeralang, Callignee, Jumbuk and Budgeree.
(5) Forests Commission - Letter dated 4 March received from Forests Commission advising its intention to spray land recently purchased in the Ryans Creek domestic water supply catchment for the planting of Pinus Radiata to reduce competition from grasses it is proposed to spray with Vorox A.A.
MINUTES OF THE ONE HUNDRETH AND NINETEENTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 21/5/76.
2. APM Forests: Letter dated 30th April received from APM indicating that the firm intends to spray, two new areas in the Parish of Stradbroke, for pre-emergent weed control with the chemical Simazine. P2 To ascertain what effect a spray of 1.51 b per hectare with 2,4,5-T has on a stream . . . Run off will not occur until good rains have fallen, at which time the peak levels of chemicals getting into streams and reservoirs can be calculated. It was thought that because of the method of measuring the effect on streams it was not necessary to monitor every operation. It may be more beneficial if samples were taken from reservoirs instead of streams. . . This aspect brings about a concern that very heavy criticism could be leveled at an organization if it was thought that the communities health is being endangered . . . It was considered that spraying should go on for a considerable time because peaks are short but they are there. A thought must be given to what people will end up with in their drinking water . . . 2,4,5-T has been detected well downstream in the Ovens River and when it was traced it was learned that it came from Buffalo Park. Decision: a) To ask the Forests Commission to prepare a program of spraying and monitoring which would be able to show effects of chemicals consistent with distances away from point of application.
MINUTES OF THE ONE HUNDRETH AND TWENTY THIRD MEETING OF THE PESTICIDES REVIEW COMMITTEE 17/9/76.
Forests Commission Letter dated 12/8/76 concerning aerial spraying of two areas of pine plantations, with herbicides, totaling approx 600 ha of very steep rough country in the Yarram district. The herbicides to be used are Weedagol T.L. Plus and Gesaprim 500 FW mixed together in water to which the surfactant Plus 50 has been added.
Decision: To advise the Forests Commission that the Committee has no objection to the conduct of the spraying as set out.
MINUTES OF THE ONE HUNDRETH AND TWENTY FIFTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 26/11/76.
(1/1) APM Forests Pty Ltd letter dated 30th Sep 1976, received from APM advising the intention to use 1080 for vermin control in various areas of pine plantations. During discussion on this notification it was thought that the description of the animals to be controlled could be more explicit and be named. The word vermin should be illuminated from future use.
(2/1) APM Forests Pty Ltd. Letter dated 4/11/76 received from APM advising the intention to use 2,4,5-T early in December 1976, in various areas of pine plantations. Although there was no objection to the conduct of the work as indicated, it was considered that it was very doubtful if it was possible for the sprayer to achieve the objective of leaving natural drainage areas untouched. Monitoring in some of the difficult places are not possible and specific study areas should be established and definite techniques should be adhered to.
Decision (b) . . . but that more information, on the rates of the chemical used, and the type of aircraft used to obtain the result of a 20m width of non-sprayed drainage lines, would be appreciated. Item 31 2,4,5-T Papers and Queries Letter dated 9th Nov 1976, received from Commission of Public Health enclosing a copy of a letter from CCV requesting info on 2,4,5-T, also a letter from EPA enclosing a copy of similar letter requesting the same information.
MINUTES OF THE ONE HUNDRETH AND TWENTY SIXTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 25/2/77.
(1/1) APM Forests Pty Ltd letter dated 26th Jan received from APM requesting consideration of a spraying program with 2,4,5-T in a young plantation of pines in the Parish of Loy Yang. Decision: To advise APM that the letter was discussed and that, although this area does not appear on previous notifications the Committee does not object to the work being carried out as advised.
MINUTES OF THE ONE HUNDRETH AND TWENTY SEVENTH MEETING OF THE PESTICIDES REVIEW COMMITTEE 1/4/77.
Item. (1/1) APM Forests Pty Ltd: Letter dated 4th Nov received from APM which was discussed at 126th Meeting. As a result of the discussion it was generally agreed that APM was not researching 2,4,5-T after spraying. Decision: 26.11.76 (a) That Dr Craig prepares a factual paper, for consideration of a code of practice on intergrated sampling . . . (b) To advise APM of the Committees various decisions and its comments about the type of aircraft used and the rate of chemical used.
The trend to intensive forest utilisation has led to adoption of clear-cutting practices and short crop rotation times on a large scale. In addition, regeneration of clear-cut sites is often with exotic trees such as the introduced softwood, Pinus Radiata or with more commercially desirable Eucalyptus species not native to the area. The end result of these practices will be a forest resource composed mainly of pine plantations and manipulated immature eucalypt forests managed in both cases as a mosaic of harvesting coupes each containing an even aged stand of trees. Where possible the coupes will be regenerated as monocultures - single species stands.
Management of even aged monocultures requires the weeding out of unwanted plants. In forestry this is being achieved increasingly by the large scale application of herbicides. The major “weeds” are the original native broadleaved plants (mainly Eucalyptus and Acacia species) and the perennial broadleaved noxious plants (such as the blackberries, Rubus species) which germinate on the harvesting coupe and compete with the regenerating forest crop. These unwanted plants are categorised as “woody weeds” and the favoured method of clearing dense stands from pine plantations or overgrown clear-cut sites prior to planting with commercial eucalypts is by aerial application of the butyl ester of 2,4,5-T in fuel oil (Flinn and Hopmans, 1977; McKimm and Hopmans, 1978). This practice is now thought to present very substantial risks to human health and natural ecosystems and led directly to the current suspension of the manufacture, distribution and use of 2,4,5-T in the United States (U.S.E.P.A., 1978; 1979a; 1979b) yet Australian forest managers seem unaware of the reasons.
The Discovery and Development of 2,4-D and 2,4,5-T
The plant growth hormone indolacetic acid, an auxin, was discovered in the 1930’s.
2,4-D was developed as a synthetic version in 1941 and it was found that an overdose touched off uncontrolled growth in broadleaved plants and killed them.
2,4,5-T was synthesized soon after and was found to have similar properties. These herbicidal properties were seen to be of great military value so 2,4-D, 2,4,5-T and many similar compounds were intensively tested and developed during World War II for use as chemical weopons by the U.S. Army Centre for Chemical and Biological Warfare at Camp (now Fort) Detrick, Maryland, U.S.A. (Whiteside, 1970).
Whiteside points out that the two herbicides were not tested in that role at the time for reasons outlined by George Merck, a chemist who headed the U.S. Biological Warfare Advisory Committee for the Secretary of War:
“Only the rapid ending of the war prevented field trials in an active theatre of synthetic agents that would, without injury to human or animal life affect the growing crops and make them useless.”
Thus 2,4-D and 2,4,5-T were originally developed for use as chemical weopons in biological warfare, not as agricultural herbicides.
After the Second World War ended, many chemicals developed and tested as chemical weopons were registered and marketed for civilian use. These included the herbicides 2,4-D and 2,4,5-T. At the time toxicological testing was not wel developed and, as the direct toxicity of the two herbicides appeared low in experimental animals, they were sanctioned for widespread sae and use by all relevant U.S.Governmental agencies. Their use for domestic agricultural and forestry purposes was heavily promoted. Extensive testing of the herbicides since 1960 has shown that this early faith was poorly based (U.S.E.P.A., 1978; 1979a; 1979b; Warnock and Lewis, 1978; Whiteside, 1970; 1977).
Chlorinated Phenoxy Acid Herbicides and their Contaminants
2,4-D and 2,4,5-T are the most widey used herbicides in the world and they belong to a group known as the chlorinated phenoxy acid herbicides that includes other herbicides such as 2,4-DB; 2,4-DES; 2,4,5-TP; and MCPA. Details can be found in the pubication “Herbicides of the Phenoxyacetic Acid Type” (AS No. 1175-1976, Standards Association of Australia, 1976).
2,4-D is an abbreviation of the chemical name 2,4-dichlorphenoxyacetic acid; similarly 2,4,5-T stands for 2,4,5-trichlorphenoxyacetic acid. The only difference between them is that 2,4,5-T has one more chlorine atom than 2,4-D.However, commercially each is synthesized from different raw materials and as a consequence, each contains a different set of unwanted contaminants. The contaminants present in mass produced agricultural and industrial chemicals are critical as it is generally uneconomic to remove them for normal use.
2,4,5-T and 2,4,5-TP are both manufactured from 2,4,5-trichlorphenol. 2,4,5-trichlorphenol is produced by reacting 1,2,4,5-tetrachlorobenzene with methanol and sodium hydroxide under high temperature and pressure. During this process, small amounts of 2,3,7,8 tetrachlorobenzo-para-dioxin (“TCDD” or “dioxin”) are inevitably produced. TCDD production can be controlled but not eliminated.
Thus 2,4,5-T and 2,4,5-TP are inevitably contaminated with 2,3,7,8-TCDD. This chemical is the most toxic substance known and it has caused several large scale poisonings (Whiteside, 1977) the best known being that at Seveso in Italy in 1976.Although the recent grave concern about 2,4,5-T and 2,4,5-TP has centered around this contaminant, 2,4,5-T with the lowest possible levels of TCDD has now been shown to produce adverse effects in experimental animals (U.S.E.P.A., 1978, 1979a; 1979b).
2,4-D and 2,4,5-T also contain a spectrum of other contaminants including other polychlorinated dioxins, various polychlorinated dibenzo-furans and polychlorinated diphenyl-ethers as well as traces of the original chemical reactants from manufacture (Ramel, 1978). Many of these could have as yet unknown adverse biological properties.
Chemical Warfare in Vietnam
From 1945 onwards testing and experimentation with herbicides as military weopons continued at Fort Detric and 1,200 compounds were assessed. By 1960 the U.S. military had settled on the use of four herbicidal sprays which were named from their colour codes:
Agent Orange:-50%n butyl ester 2,4-D; 50%n butyl ester 2,4,5-T
Agent Purple:-50%n butyl ester 2,4-D 30% n butyl ester 2,4,5-T 20% iso butylester 2,4,5-T
Agent White:-20% picloram 80% amine salt
Agent Blue:-65% cacodylic acid (dimethylarsenic acid); 35% inert salts
As part of the U.S. Vietnam war program, large scale application of herbicides commenced in 1961 and ended in 1971. In that time 4,119,960 acres of forest were defoliated and 468,559 acres of crops destroyed (Whiteside, 1970). The operation, known publicly as “Operation Ranch Hand” was officially designated by the code name “Operation Hades”. Agent Orange was the most extensively used herbicide and, as forests were the main target, the Aerial Spray Flight of the 309th Aerial Commando Squadron U.S.A.F. who conducted the campaigns, adopted the slogan “Only we can prevent forests” (Hersh, 1968).
When the extent of the damage done by herbicides in South Vietnam became known in the late 1960’s there was a massive backlash against U.S. chemical warfare from the U.S. and international communities. Scientists, technologists, servicemen, industrialists and politicians who had co-operated in the chemical warfare program in Vietnam suddenly found themselves accused of carrying out ecocide and genocide. As a result guilt reactions surfaced and attitudes towards herbicides hardened. Subsequently a team of scientists appointed by the National Academy of Sciences reported widespread ecological damage in Vietnam from the use of herbicides.
Owing to its widespread use, Agent Orange became synonymous with chemical warfare in Vietnam. Thus reactions to the civilian use of 2,4-D and 2,4,5-T became linked to reactions to the Vietnam War and its after effects. This factor, more than any other, has obstructed objective assessment of the risks presented by the two herbicides as many scientists, industrialists and politicians are basically intent on justifying their actions up to 1971.
Stories about adverse human health effects from the use of herbicides in Vietnam also started to circulate in the late 1960’s. In particular high rates of birth defects and spontaneous abortions were reported from areas heavily sprayed with Agent Orange. Serious questions suddenly emerged about the safety of the herbicides 2,4-D and 2,4,5-T to humans. The N.A.S. investigating team could not substantiate any adverse effects but stressed that basic epidemiological study requirements cannot be met in a population involved in a protracted state of war.
The Bionetics Report
The Bionetics report on 2,4,5-T was part of a series of tests carried out under a $2.5 million contract from the National Cancer Institute to screen more than two hundred chemicals, mostly pesticides, for birth deforming (teratogenic), cancer inducing (carcinogenic) and genetic (mutagenic) effects in laboratory mammals. These tests were carried out by the Bionetics Research Laboratories in Bethesda, Maryland.
In their tests 2,4,5-T did not appear to induce cancer in laboratory animals used and these results were released publicly in March, 1969. However, the results of the teratological tests were initially withheld even from members of the panel who were considering the teratogenic potential of pesticides. These tests had shown that 2,4,5-T caused birth deformities in rats and mice. Even when the results were eventually circulated to relevant governmental agencies, nothing was done to limit 2,4,5-T use. Finally some students working with Ralph Nader located a copy of the preliminary teratological report and told Harvard Biology Professor Matthew Meselson who obtained “bootlegged” copies from Washington officials in October, 1969. After reading the report Meselson was so alarmed that he contacted the Army and the White House and a collegue informed the press. As a result, Dr Lee DuBridge, President Nixon’s science advisor released a statement on 29th October, 1969, that said in part:
“…findings from a laboratory study conducted by Bionetics Research Laboratories indicated that offspring of rats and mice given relatively large oral doses of the herbicide (2,4,5-T) during the early stages of pregnancy showed a higher than expected number of deformities.”
This was, in fact, a gross understatement of the results - the 2,4,5-T used in the study caused excessive foetal mortality (80%) and high rates of birth abnormalities at the higher doses (100% at 46.4 mg/kg body weight and 90% at 21.5 mg/kg body weight) but there was excessive mortality and a threefold increase in birth abnormalities in survivors even at the lowest dose used (4.6%mg/kg body weight).
Once the Bionetics data on birth abnormalities and foetal mortality was released, action against 2,4,5-T seemed inevitable.The chemical industry cast around desperately for an explantation of the results that would not implicate 2,4,5-T itself. Dow Chemical Company scientists discovered that the 2,4,5-T used in the Bionetics study was obtained from the Diamond Shamrock Company in 1965. This company no longer manufactured 2,4,5-T in 1969 - thus the herbicide used in the tests was labelled as unrepresentative of the 2,4,5-T then in production.
Dow scientists also discovered that the 2,4,5-T used in the tests contained comparitively large amounts of the contaminant 2,3,7,8 TCDD or “dioxin” which is normally present in only trace amounts. Thus the 2,4,5-T used in the Bionetics study was also labelled as grossly contaminated with the most toxic chemical known. It was revealed that the 2,4,5-T used in the study contained 15-30 parts per million (ppm.) whereas the 2,4,5-T being produced in 1969 contained less than 1ppm TCDD.
Since 1969 TCDD levels have been reduced to less than 0.1ppm TCDD, but recent tests have shown this “pure” 2,4,5-T to be teratogenic in test mammals at dose levels down to 20 mg/kg body weight (U.S.E.P.A., 1978; V.C.C., 1978) and possibly even to 10mg/kg body weight (U.S.E.P.A., 1979a; 1979b).
As TCDD levels cannot be further reduced, it is now generally accepted that 2,4,5-T with its inevitable low level TCDD contaminant is teratogenic in test mammals with a no adverse effect level at about 20 mg/kg body weight. This was recognized by the Victorian Consultative Council on Congenital Abnormalities set up to investigate the Yarram cluster of birth abnormalities in 1975-76 (V.C.C., 1978).
This point has been misunderstood or misrepresented by many Australian forestry authorities. They apparently believe that only the Bionetics Report showed 2,4,5-T to be teratogenic, that the effects were due to the exceptionally high TCDD levels (“up to 50 ppm.”) and that since levels of TCDD were reduced to 0.1 ppm, or less 2,4,5-T has not been shown to be teratogenic.
Principles Governing Toxicological Evaluation
To safeguard public health it is essential to assess the effects that synthetic chemicals like 2,4,5-T have on humans. This is achieved in three ways:
(1) Epidemiology: Direct observation on human health where carefully collected statistics from populations exposed to the chemicals are compared to equivalent statistics from unexposed control populations. These data can be directly interpreted to set public health criteria.
(2) Laboratory Tests: Observation of biological effects on laboratory organisms exposed to set doses of the chemical compared to equivalent unexposed laboratory organisms. These data can only be very cautiously extrapolated to humans to set public health criteria.
(3) Exposure Analysis: Careful analysis of chemical pathways in the environment and measurement of actual flow rates. These data can then be used to calculate human exposure from possible absorption via skin contact, ingestion with food and drink, and inhalation with air. This information can then be used to set public health criteria in the light of the data from epidemiological or laboratory tests.
The biological effects that must be assessed include; toxic effects (systemic poisoning); carcinogenic effects (cancer induction); oncogenic effects (tumour induction); mutagenic effects (genetic changes); teratogenic effects (birth defect induction); embryotoxic effects (poisoning of the embryo); neurotoxic effects (brain or nervous system damage).
To evaluate the safety of a chemical, the U.N.F.A.O and W.H.O. have adopted a standard approach (W.H.O., 1972) which is widely accepted (N.H.& M.R.C., 1972; U.S.E.P.A., 1978; Victorian Pesticides Committee, 1966):
(1) Acceptance of a “no adverse effects level” (N.E.L.) established from epidemiological studies or in the course of some appropriately conducted long term tests of tests in laboratory organisms.
(2) Applications of an arbitrary “safety factor” (S.F.) which is in keeping with the nature of the chemical being tested, with the circumstances of its intended use, with the effect being tested, and the quality of the experimental studies available.
(3) Allocation of unconditional, conditional or temporary “acceptable daily intakes” (A.D.I.’s) where appropriate by dividing the “no adverse effects level” by the “safety factor”, i.e.:
For “pure” (i.e. low level TCDD) 2,4,5-T the teratogenic N.E.L based on laboratory animal experiments is accepted to be 20 mg/kg body weight per day (V.C.C., 1978; U.S.E.P.A., 1978) but it may need to be lowered to 10 mg/kg body weight per day in future (U.S.E.P.A, 1979a; 1979b).
For TCDD the teratogenic N.E.L. based on laboratory animal experiments is accepted to be 0.03 mg/kg body weight per day (V.C.C., 1978; U.S.E.P.A, 1978) but the U.S. E.P.A. has recently suggested there is no N.E.L. (U.S.E.P.A., 1979a; 1979b).
To set an adequate safety factor is more complex. Where the N.E.L. has been estimated from reliable epidemiological data (e.g. mercury on the population of Minimata in Japan) a small safety factor of 10 can be adopted (N.H. & M.R.C., 1972; W.H.O., 1972). Where the safety factor must be set from experimental animal data, a safety factor of at least 100 must be adopted as data from other animal species cannot be directly applied to humans (N.H. & M.R.C., 1972; V.P.C., 1966; W.H.O., 1972).
With teratogenic effects from laboratory tests, the safety factor must be even larger as thalidomide proved to be up to 700 times more potent in epidemiological studies on humans than in laboratory animal tests (Warnock and Lewis, 1978). Thus a safety factor of 1,000 is normally applied. For pesticides the W.H.O. recommend a safety factor of 2,000 as they have a strong chance for incorporation into human tissues (Whiteside, 1970). The safety factor recognized by the U.S.F.D.A and the U.S.E.P.A. is 2,000 (Whiteside, 1970; U.S.E.P.A, 1978). Strangely, the New Zealand Government enquiry into 2,4,5-T and birth deformities (N.Z. Department of Health, 1977) rejected the 2,000 safety factor but did not set an alternative - at best this would be 100. The Victorian Consultative Council on Congenital Abnormalities (V.C.C., 1978) did not even discuss safety factors but directly applied N.E.L. teratogenic data from laboratory tests to humans.
Thus for 2,4,5-T the safety factor to be applied to teratogenic N.E.L.’s from animal experiments is 2,000. For TCDD there may be no safety factor (U.S.E.P.A., 1979a; 1979b).
The A.D.I. for 2,4,5-T then, is the teratogenic N.E.L. - 2,000, at current values this is 0.01mg.kg body weight. This would need to be lowered to 0.005 mg/kg body weight if the N.E.L. is lowered. For TCDD there is probably no A.D.I.
The Victorian Consulatative Council on Congenital Abnormalities quoted an A.D.I. for teratogenic effects in humans of 20 mg/kg body weight for 2,4,5-T and 0.03 uu/kg weight for TCDD.
Uses of 2,4,5-T
Like 2,4-D, 2,4,5-T is similar to the indolacetic acid plant growth hormones (auxins) so it is often referred to as a hormone spray. In broadleaved plants (dicotyledonous angiosperms) such as wattles or eucalypts, an overdose of 2,4-D or 2,4,5-T causes uncontrolled tissue growth that kills the plant. The exact chemical basis of this effect is not yet clear but it has been likened to malignant cancer in animals (Warnock and Lewis, 1978). This lethal effect in broadleaved plants is not replicated in grasses (monocotyledonous angiosperms) such as wheat or rice, or in conifers (gymnosperms) such as pines.
Thus 2,4-D and 2,4,5-T are selective herbicides - they kill broadleaved plants but do not affect grasses or conifers.2,4-D is widely used on annual broadleaved weeds in grain crops, on grazing pastures, on recreation areas and on domestic lawns. 2,4,5-T is much more effective against “woody broadleaved weeds” - trees and perennial weeds such as blackberries and consequently has much more limited use.
Forestry Uses of 2,4,5-T
Most forestry “weed” problems involve unwanted broadleaved trees or perennial broadleaved plants, so 2,4,5-T is the most widely used herbicide. Major uses include the killing of unwanted broadleaved trees such as wattles in site clearance prior to replanting with commercially desirable eucalypts and the control of regenerating wattles and eucalypts and noxious weeds in pine plantations. (Dargavel and Hall, 1978; Flinn and Hopmans, 1977; McKimm and Hopmans, 1978).
Technical 2,4,5-T is available in two basic forms - as a water soluble amine salt or as a much more dangerous, volatile, oil soluble ester. The esters are the commonest form of forestry use, especially for spraying. Details of use of 2,4,5-T in Australian forestry can be found in Dargavel and Hall, 1978, (Australian and New Zealand pine plantations); Flinn and Hopmans, 1977, (Victoria); Forrest and Richardson, 1966, (New South Wales); and McKinnell and Butcher, 1973, (Western Australia).
In Victoria 2,4,5-T has its largest application “weeding” wattles from pine plantations and Flinn and Hopmans (1977) detail the practices. For low density wattle regeneration, manual applications of basal bark sprays or stem injections may be used.
However, the main method of application is low volume aerial spraying of the volatile butyl ester at the rate of 1.1kg 2,4,5-T in 50 litres of dieseline per hectare. Since this practice started in 1968, 17,981 hectares of publicly owned pine plantations have been treated this way - an average of 1,998 hectares per year (F.C.V. Annual Reports, 1968/69 - 1977/78). This represents 23.4% of the total publicly owned pine plantation area (76,860 hectares, F.C.V., Annual Report, 1977/78) or 2.6% per annum. No figures are available for privately owned pine plantations but the publicly owned resource is only about 50% of the state total so the total area treated since 1968 may be in the order of 36,000 hectares.
Hazards of Low Volume Aerial Spraying with 2,4,5-T
Low volume spraying is a euphemism for high concentration spraying where only 50-100 litres of diluent are used per hectare. In high volume spraying, 500-1,000 litres of diluent are used per hectare to spread the same amount of herbicide (McKinnell and Butcher, 1973).
Low volume aerial spraying of 2,4,5-T as practiced in forestry is exceedingly dangerous as a high concentration of the volatile butyl ester is applied to the target area as a dense mist from a height of about 30 metres. Spray drift and vapour drift are major problems and spraying cannot be carried out on windy days. The U.S.E.P.A. (1979a) records that 2,4,5-T spray drift has caused damage to susceptible plants 35 kilometres from a target area. Butcher and McKinnell (1973) record that air concentrations of 2,4,5-T down to 10 parts per billion (ppb.) kill susceptible plants (tomatoes) which works out to 0.0267 mg/cubic metre of air. Thus there is biological evidence of air concentrations of 2,4,5-T above 0.02mg/cubic metre 35 kilometres from a spray area. Is this concentration hazardous?
With regard to teratogenic effects, the acceptable daily intake (A.D.I.) is 0.01 mg 2,4,5-T/kg body weight. As a woman weighs 60 kg on average, the total A.D.I. is 0.6 mg. Each adult breathes about 30 cubic metres of air per day and 100% of the inhaled herbicide is absorbed (U.S.E.P.S., 1978). Thus on an A.D.I. basis the maximum allowable air level is 0.02mg/cubic metre. Spray drift up to 35 kilometres from a target area must therefore be considered hazardous to women in the child bearing age group.
The Australian National Health and Medical Research Council (N.H. & M.R.C.) set a maximum allowable air level of 10 mg/cubic metre of air for 2,4,5-T - 1,000 times the A.D.I. level for teratogenic effects; the level set for 2,4-D is 200mg/m3. (N.H. & M.R.C., 1975).
McKimm and Hopmans (1978) documented the amount of spray drift from a target area in a carefully controlled experiment on low volume spraying with 2,4,5-T at Narbethong carried out under optimal spraying conditions. They record from 30 metres only 65% (0.75kg/ha.) was recovered at ground level and they comment that this is in the upper range of expected recovery. In other words, at best, one third of the spray applied aerially moves immediately from the target area even in calm weather. Is this hazardous?
Of the 1.1kg of 2,4,5-T applied to each hectare during low volume aerial spraying, at least 35% or 0.385kg is lost to the general air mass as vapour and spray drift. With regard to teratogenic effects the maximum allowable air level is 0.02mg/cubic metre. The 0.385 kg of 2,4,5-T lost to the air during the spraying of each hectare of pines would contaminate 19,250,000 cubic metres of air to this level, or the air 641,667 women would breathe in one day.
In a decade 17,981 hectares of publicly owned pines have been aerially sprayed with 2,4,5-T. The spray and vapour drift during spraying (0.385 kg/ha.) is enough to contaminate the air 11.5 billion women would breathe in one day to above the A.D.I level.
Another major environmental hazard of low volume aerial spraying is volatisation of the spray from the target area in the weeks after spraying is completed. McKinnell and Butcher (1973) state that the butyl esters of 2,4,5-T should not be applied in hot weather and recommend spraying only when air temperature is below 24 degrees C. They record the butyle ester of 2,4,5-T has a vapour pressure of 7 mg/cubic metre of air at 30 degrees C; 16 mg/m3 at 40 degrees C; and 85 mg/m3 at 60 degrees C. To illustrate the highly volatile nature of the butyle ester, they record that the vapour pressure of the butoxyethyl ester is only 1 mg/m3 at 30 degrees C; and of the amine salt, 0 mg/m3 at 30 degrees C. In passing they comment that 2,4-D is even more volatile than 2,4,5-T.
With regard to teratogenic effects, the total A.D.I. is only 0.6 mg per adult woman. If the air were saturated with 2,4,5-T at 30 degrees C. (7 mg/m3), a woman would have to breathe the air for just over six minutes to exceed the risk level. Further, on an A.D.I. basis with regard to teratogenic effects, the maximum allowable air level is only 0.02 mg/m3. Clearly women in the vicinity of an area recently sprayed with the butyl ester of 2,4,5-T are at risk, especially during hot weather.
2,4,5-T Residues in Stream Water after Aerial Spraying
One other major environmental hazard with aerial spraying of 2,4,5-T is the contamination of runoff water from the target area. In 1972 the Forests Commission of Victoria continuously monitored 2,4,5-T levels in a small stream draining a spray site in a pine plantation at Myrtleford. McKimm (1972) reported that immediately following spraying low and quite acceptable concentrations of 2,4,5-T were found, and this condition obtained until the first rain after spraying, when the concentration in the stream rose rapidly. No figures were given but the report implied that after rain the levels obtained were unacceptable i.e above the standard of 20 ug.litre (20 ppb.) set by the National Health and Medical Research Council.
In June 1973 the F.C.V. carried out a larger study in 1 335 hectare section of a pine plantation in a catchment of Clear Creek near Myrtleford. Four stream sample points were established at varying distances from the spray area and a total of 1,000 samples were collected over a ten day period. Major peaks in 2,4,5-T concentration occurred after rain, and lesser, relatively insignificant, peaks also occurred during spraying (McKimm, 1974). McKimm stated that 2,4,5-T concentrations were in excess of the upper limit of 20 ug/litre set by the N.H. & M.R.C. but he did not list values. In fact, at the sampling point immediately below the spray zone values of 75 ug/l were obtained during spraying and peaks up to 690ug/l were obtained after rain. Three kilometers downstream values of 135 ug/l were obtained during spraying and peaks up to 500ug/l were obtained after rain. Worse, for the sampling point immediately below the spray zone, of 83 readings made during the seven days after spraying, 48% (40) exceeded 20 ug/l.; 14% (12) exceeded 50 ug/l.; and 7% (6) exceeded 100 ug/l. These measurements indicated that there was a significant threat to streams in aerially sprayed areas, but nothing was done. Rather, two new monitoring programs were organised, one at Carboor near Myrtleford and another at Narbethong in the Central Highlands.
The study at Carboor wa carried out in 1977 on a spray site of 162 hectares in the Scrubby Creek catchment. After the pine plantation was sprayed concentrations of up to 4.2ug/l were measured in a culvert draining the target area, but in Scrubby Creek concentrations remained below 0.3ug/l. (McKimm and Hopmans, 1977). The Narbethong study was carried out in July 1977 on a spray site of 108 hectares in the Old Mill Stream catchment. After the pines were sprayed concentrations in the Old Mill Stream were all below 4.4 ug/l except for one value of 10ug/l measured on the seventh day after spraying (McKimm and Hopmans, 1977; 1978).These two studies convinced the Forests Commission that aerial spraying presents no real threat to water quality (Flinn and Hopmans, 1977).
Regulation of Aerial Spraying with 2,4,5-T in Victoria
Australian pesticide authorities regularly invoke circular arguments on public risk. Firstly they recommend spray concentrations and practices which according to theoretical calculations should protect public health. Next, when publicity is given to a particular risk, they state that if the pesticide is used in accordance with their recommendations the pesticide presents no risk and the calculations used to formulate the recommendations are then repeated to prove the point. The real problems however, are that pesticides are often not used according to recommendations; that statuatory controls are weak or non-existent; and that enforcement is poor.
From the sections on the hazards of low volume aerial spraying and residues of 2,4,5-T in stream water, it can be seen that the aerial spraying of the butyl ester of 2,4,5-T should only be carried out in cool, calm, dry weather.However, aerial spraying is a capital intensive business and growing seasons dictate spraying times. Thus aerial spraying schedules are organized mainly on business commitments and not climatic considerations. It is informative to examine the statutory controls.
The Aerial Spraying Control Act 1966 as amended in 1968, 1970 and 1978, is the relevant parliamentary Act. This Act does not limit spraying activities in areas where human populations or natural ecosystems can be threatened. In fact, the Act is primarily designed to protect private property and commercial crops.For example spraying may not be carried out in “hazardous areas”, but these are defined as areas carrying susceptible crops.
The Aerial Spraying Control Regulations 1966 as amended in 1968, 1969, 1971 and 1977, detail the statutory rules for enforcement of the Act. The Fourth Schedule lists eight herbicides, including 2,4-D, 2,4-DB, 2,4,5-T and 2,4,5-TP which must be used under special controls. These include a prohibition on aerial spraying with ester formulations over or within 8 kilometres (5 miles) of any hazardous area.
Thus the Aerial Spraying Control Act and Regulations recognize that spray and vapour drift of the esters of 2,4-D and 2,4,5-T and related products can cause damage to susceptible plants at distances of up to eight kilometers.
The Act and Regulations exert statutory controls over aerial spraying of 2,4,-D and 2,4,5-T where economic damage to crops can result but spraying near natural ecosystems or human habitation is not controlled. Such controls have been left to the “Code of Practice for Large Scale Application of Pesticides in Victoria” issued by the Premiers Department in December, 1966. The Introduction of the Code reads:
“All governmental agencies are required to consult with the Pesticides Review Committee before proceeding with the large scale application of pesticides. Additionally, commercial organizations, particularly those operating within forested areas are encouraged to seek the advise and approval of the Pesticides Review Committee.”
The Code of Practice has no statutory powers. Thus with respect to risks to human health and natural ecosystems there are effectively no legal controls.
Aerial Spraying Incidents in Victoria
Two recent incidents in South Gippsland illustrate the deficiencies of legal controls over aerial spraying. The first relates to the spraying of a property known as Brigadoon Park at Seaview with 2,4-D and possibly some 2,4,5-T on the 7th of October, 1977. Although the farmhouse, water storages, garden and residents were saturated with spray and the garden was destroyed, the spray pilot and spray firm could not be charged with any breach of the Aerial Spraying Control Act or Regulations. Eventually the company, Skyfarmers Pty Ltd, were taken to court on twelve charges relating to breaches of the Environment Protection Act, 1970. They were found guilty on four of the charges in a written decision on 6th February, 1979 and fined $1000 with $3,130.80 costs.
The second incident occurred at Leongatha on the 15th of January, 1979, when 200 patrons at a drive-in theatre were sprayed with the fungicide Polyram 2000 at 8.55pm. Patrons and theatre staff complained of irritation to the eyes, ears and nose but once again the pilot and spray firm did not breach the Aerial Spraying Control Act or Regulations so no charges could be laid. The theatre projectionist said that a south-easterly wind had blown the chemical onto the drive-in and added “I reckon it’s a crying shame to have a plane spraying the stuff virtually in the town.”
These two incident show clearly that recommended aerial spraying practices are not always followed and that as a consequence direct human exposure can result without breaching the Aerial Spraying Control Act or Regulations. While it is illegal to spray 2,4-D or 2,4,5-T within eight kilometers of a susceptible crop, it is legal to spray immediately adjacent to houses and towns, and accidental (or deliberate) spraying of human habitation does not constitute an offence under the Act.
If the proponents of the aerial spraying of pesticides are sincere about the effectiveness of their recommended precautions, they should back up their beliefs with strict statutory controls to protect public health.
Controls of 2,4,5-T in Australia
Technical aspects of pesticide use in Australia are under the control of the Australian Agricultural Council. Health aspects are controlled by the National Health and Medical Research Council (N.H. & M.R.C.) who recommend acceptable residue levels for food and water and also which poisons schedule a pesticide is to be placed in. The N.H. & M.R.C. can also recommend any special restriction to be placed on a pesticide. State government authorities are expected to follow N.H. & M.R.C. recommendations in establishing statutory controls.
The role of the N.H. & M.R.C. in assessing the teratogenic properties of 2,4,5-T bears close scrutiny as it explains why no restrictions on public exposure have been made in Victoria.
In 1972 at its 75th Meeting, the N.H. & M.R.C. “…considered recent reports of teratogenic abnormalities in mice and rats following administration of large oral doses of the weedicide 2,4,5-T.” No references were provided but this was probably the Bionetics Report. The Council made three unequivocal recommendations that:
(i) all persons exposed to 2,4,5-T in its manufacture and use should use special precautions, such as protective clothing, to ensure that skin absorption does not occur.
(ii) Women in the child bearing age group should not be exposed to 2,4,5-T.
(iii) The residues of 2,4,5-T in water supplies should not exceed 0.02 parts per million.
Thus the Council acknowledged that 2,4,5-T caused birth abnormalities in laboratory mammals and that there was a consequent risk to humans.
In 1975 at its 80th Meeting, the N.H. & M.R.C. “…considered the most recent reports of teratogenesis following the adminstration of large oral doses of 2,4,5-T and considerd that the available evidence indicated that the impurity tetrachloro-dibenzo-para-dioxin (TCDD) was the agent implicated in congenital abnormalities.” The statement was simply not true and is completely contradicted by the U.S. E.P.A. reports (1978; 1979a; 1979b) and the Victorian Government Yarram Enquiry (V.C.C., 1978). The N.H. & M.R.C. report concludes:
“Council therefore rescinded the recommendations on 2,4,5-T made at its Seventy-fifth Session.
“Council recommended that 2,4,5-T containing more than 0.1 ppm. should not be permitted for use as a herbicide in Australia and that there should be a maximum residue limit of 0.02 ppm. 2,4,5-T permitted in water.”
In summary, in 1972 the N.H. & M.R.C. actually recommended women in the child bearing age group should not be exposed to 2,4,5-T because of its teratogenic effects on laboratory mammals. The Council rescinded this recommendation in 1975 despite the fact that new studies on laboratory animals had confirmed the original results even for 2,4,5-T with levels of TCDD below 0.1 ppm.
Since that time the N.H & M.R.C. has not publicly commented on the demonstrated teratogenic properties of 2,4,5-T with low levels of TCDD on laboratory mammals. Instead they have shifted ground and are now maintaining that teratogenic effects have not been demonstrated in humans. For example, at the 85th Session in 1978 they stated “Council could find no substantiated scientific evidence of a causal link between the use of 2,4,5-T and human birth defects.”
The Council have now completely abandoned their cautious 1972 stand where they were prepared to prevent a possible human disaster by extrapolating the results of tests on laboratory mammals to humans and ban the use of 2,4,5-T where women in the child bearing age group could be exposed. Now the Council are going to wait for substantiated evidence of a human disaster before they will take action.
Even worse, when epidemiological studies showing adverse reproductive effects in women exposed to 2,4,5-T have been published, the N.H. & M.R.C. have rejected them without explaining publicly why they are unacceptable. For example, the U.S. E.P.A. report showing a high rate of miscarriages in women exposed to 2,4,5-T in Alsea, Oregon, from 1972 to 1977 (U.S. E.P.A., 1977a) and the University of Sydney report showing a direct correlation with 2,4,5-T usage and the incidence of neural-tube defects in babies born in New South Wales from 1965 to 1976 (Field and Kerr, 1979) were both rejected. On the other hand reports purporting to show no adverse effects (e.g. the Yarram Enquiry Report, V.C.C., 1978) appear to have been accepted without close scrutiny.
To overcome these problems, the N.H. & M.R.C. should be forced to estimate a no adverse effects level (N.E.L.) for teratogenic data on laboratory mammals; state what the appropriated safety factor for human exposure is for this data; and from these calculate an acceptable daily intake (A.D.I.) level for women in the child bearing age group. From the A.D.I., risks from exposure to 2,4,5-T can then be assessed.
The N.H. & M.R.C. are also responsible for the Poisons Schedule designation of pesticides. Of eight schedules, 2,4,5-T is designated under Schedule 6 (Anon, 1978):
“Schedule 6 - Substances or preparations of a poisonous nature which must be readily available to the public for domestic, agricultural, pastoral, horticultural, veterinary, photographic or industrial purposes for the destruction of pests”.
This schedule stresses that ready availability of 2,4,5-T must be preserved, and does not stress that there is any real threat to human health.
To summarize the above information, the N.H. & M.R.C. (1972) started off very concerned about the demonstrated teratogenic effects of 2,4,5-T on laboratory mammals and recommended severe limitations on its use to protect women in the child bearing age group. In 1975 the Council mistakenly reported that 2,4,5-T with TCDD levels below 0.1ppm. showed no teratogenic activity in laboratory mammals. Since that time they have not publicly admitted their mistake and have not commented on the demonstrated teratogenic effects of 2,4,5-T with levels of TCDD below 0.1 ppm. Rather, they have shifted ground and abandoned their original standard that if a chemical is teratogenic in laboratory mammals it presents an unacceptable risk to humans, and adopted a new standard saying that there is no risk to women until reproductive effects are substantiated from studies on exposed populations.
Such an approach from a public health body is completely unacceptable.
Controls of 2,4,5-T in Victoria
Although state authorities are expected to adopt N.H. & M.R.C. recommendations, the three recommendations on 2,4,5-T made by the Council at its 75th Session in 1972 were not acted upon by the Victorian Government. After the rescission of the 1972 recommendations by the 80th Session in 1975 and the adoption of the recommendation that TCDD levels be kept below 0.1 ppm., the Standards Association of Australia rewrote the existing “Standard for Herbicides of the Phenoxyacetic Acid Type” (AS. No. N50-1965) and reissued it in 1976 (AS. No. 1175-1976) to incorporate a limit of 0.1ppm. TCDD for 2,4,5-T. Australian Standards have no statutory powers, however, the new Standard AS. No 1175-1976 was incorporated into the Victorian Pesticides Regulations on the 6th July, 1977 (Government Gazette No. 58, 1977).
Thus the only government action taken to decrease the risk of birth abnormalities from 2,4,5-T in Victoria since it was discovered to have teratogenic effects in laboratory mammals has been to limit TCDD to 0.1 ppm or less.
Even here the action has not been dramatic. The Yarram Consultative Committee (C.C.V., 1978) reports that tests on the TCDD level in 2,4,5-T offered for sale in Victoria over the last two years averaged 0.06ppm, and one sample reached 0.2 ppm. The U.S. E.P.A. (1979a) reports that in 16 recent samples of 2,4,5-T from five manufacturers in the U.S., TCDD levels ranged from not detectable (below 0.01 ppm.) to a maximum of 0.025 ppm. Further, the U.S. E.P.A. (1979b) reports that 8 recent samples of 2,4,5-TP from two manufacturers had TCDD levels from 0.012 to 0.024. Thus the maximum TCDD level measured for Victorian samples is eight times the U.S. maximum, while the Victorian average is two and a half times the U.S. maximum.
Trade Union Action
The seriousness of the risks associated with the use of 2,4,5-T has been realized by the Victorian Trade Unions. In February, 1979, the Victorian Trades Hall Council passed a resolution banning the handling and use of 2,4-D and 2,4,5-T until the State Government introduces and properly enforces regulations that protect workers health and public exposure. The V.T.H.C. listed seven points that must be covered in such regulations - including the three recommendations passed by the N.H. & M.R.C.’s 75th Session in 1972 that were rescinded by the 80th Session in 1975.
2,4,5-T Usage in State Softwood Plantations 1969 - Area Sprayed and Amount of Herbicide Used.
In 1969-70, 271 hectares (a) were sprayed with a total of 289 kilograms a.i (b) used
In 1970-71, 1,436 hectares were sprayed with a total of 1,580 kilograms a.i used.
In 1971-72, 2,401 hectares were sprayed with a total of 2,641 kilograms a.i used.
In 1972-73, 2,798 hectares were sprayed with a total of 3,074 kilograms a.i used.
In 1973-74, 3,816 hectares were sprayed with a total of 4,198 kilograms a.i used.
In 1974-75, 2,486 hectares were sprayed with a total of 2,735 kilograms a.i used.
In 1975-76, 1,915 hectares were sprayed with a total of 2,106 kilograms a.i used.
In 1976-77, 1,107 hectares were sprayed with a total of 1,218 kilograms a.i used.
In 1977-78, 1,751 hectares were sprayed with a total of 1,926 kilograms a.i used.
In this time 17,981 hectares were sprayed in State Plantations throughout Victoria, using a total of 19,780 kilograms.
MEAN per annum 1,998 hectares. 2198 kilograms.
(a) Forestry Commission of Victoria Annual Reports 1969-70 to 1977-79.
(b) Calculated at rate of 1.1 kgm. per hectare.
Actions Against 2,4,5-T in the United States
Since the release of the Bionetics findings in 1969, 2,4,5-T 2,4,5-TP and other pesticides manufactured from 2,4,5-trichlorphenal have been the subjects of attempts to severely restrict or cancel their registrations for use owing to the inevitable presence of 2,3,7,8-TCDD. The early actions, published under Pesticide Registration (PR) Notices PR 70-8; PR 70-11; PR 70-13 and PR 70-22 in 1970 included suspension or cancellation of the following uses of 2,4,5-T:
1. All uses in lakes, ponds or in ditch drains.
2. Use around the home, recreational areas and similar sites.
3. All uses on food crops intended for human consumption.
On the 7th May, 1971, the U.S. E.P.A. committee recommended the use of 2,4,5-T be permitted on forests, rights-of-way and range-lands provided:
1. All 2,4,5-T be below 0.1 ppm. TCDD
2. 2,4,5-T be applied only once per year per site.
3. 2,4,5-T not contaminate areas where it could contact humans.
The U.S. Department of Agriculture (PR 70-22) reported that toxic chlorodioxins (such as TCDD) were always present as contaminants in basic material used in formulating 2,4,5-T. As a consequence the U.S. E.P.A. initiated action against the herbicide to cancel its registration. Dow Chemical Company obtained an injunction against the E.P.A. to stop the action on 1st July, 1972 but this was overturned in 1973.
On the 20th July, 1973, the U.S. E.P.A. filed a notice of intent to hold a hearing on the cancellation of all uses of 2,4,5-T in 1974 under the relevant Federal Act. This action was expanded on 10th May, 1974, to include all insecticides and herbicides made from 2,4,5-T trichlorphenal. However, the U.S. E.P.A. withdrew the cancellation hearings on 24th June, 1974, due to their inability to monitor dioxin. Instead, the E.P.A. held a Dioxin Conference on 25th and 26th July, 1974, and the “Dioxin Implementation Plan” (D.I.P.) was initiated. This was mainly a monitoring program and the move was strongly condemned by some (Whiteside, 1977).
Finally, as the first serious step in canceling the registration of 2,4,5-T, the U.S. E.P.A. issued a “Rebuttable Presumption Against Registration and Continued Registration of Pesticide Products Containing 2,4,5-T” or “RPAR” (Federal Register, Vol. 43, No. 78, 21st April, 1978). The Rebuttable Presumption criteria on which action was taken were:
1. “There is sufficient evidence to indicate that 2,4,5-T containing TCDD at levels as low as 0.05 ppm. and TCDD alone can produce ongenic effects in mammalian species. Since 2,4,5-T, as currently formulated, contains TCDD (at a maximum amount of 0.099 ppm.), a rebuttal presumption against registration of 2,4,5-T products has arisen because of the oncogenic effects of 2,4,5-T and TCDD.”
Thus 2,4,5-T and/or its contaminant TCDD are presumptive cancer risks in humans.
2. “2,4,5-T containing TCDD, 2,4,5-T without detectable TCDD and TCDD alone, produce fetotoxic and teratogenic effects in mammals.”
Thus 2,4,5-T and/or its contaminant TCDD are presumptive teratogenic and abortificant agents in humans.
3. “With regard to reproductive effects in mammals, an ample margin of safety does not exist for the population at risk (women of child bearing age) for dermal and inhalation exposure and for cumulative oral, dermal and inhalation exposure to both 2,4,5-T and TCDD.”
Thus exposure to 2,4,5-T in its normal registered uses is not safe for women in the child bearing age group.
As a result of information collected under the RPAR process, the U.S. E.P.A. took the strongest action possible against a registered pesticide on the 28th February, 1979 when it issued an “Emergency Suspension Order” for 2,4,5-T and 2,4,5-TP. The Order cited the 1978 criteria plus the result of an epidemiological study on the frequency of spontaneous abortions of women living in the Alsea area of Oregon where extensive aerial spraying of pine forests with the butyl ester of 2,4,5-T takes place every year. The study examined the frequency of spontaneous abortions during the first twenty weeks of pregnancy for women living in Alsea compared with data for women living in a non-exposed control area. For the six year period 1972 to 1977 there was a statistically significant increase in spontaneous abortions for the women in Alsea and the excess numbers in Alsea were seasonal and inevitably occurred shortly after the use of 2,4,5-T on pine forests in the area to kill broadleaved woody weeds.
The Emergency Suspension Order immediately halted the distribution, sale and use of 2,4,5-T and 2,4,5-TP in U.S. forests, rights-of-way and pastures as an imminent hazard to humans existed from the next forestry spraying season.
These U.S. actions were investigated by the Australian N.H. & M.R.C. in March 1979. A ten member committee of the Council found:
“The (U.S.) report did not substantiate the conclusions therein nor did it provide a basis for concluding whether 2,4,5-T causes or does not cause an increase in spontaneous abortions.”
These findings were accepted by the N.H. & M.R.C. Session in June, 1979 and the Chairman of the Commonwealth Health Department commented that the 2,4,5-T controversy was “…a comedy of errors except there is little humor in it.”
The credibility of the Council’s findings on the Alsea report, however, were suspect in the light of the 1975 rescission of the 1972 recommendation relating to the teratogenic effects of 2,4,5-T on laboratory mammals. Even more damaging was the revelation on 23rd May, 1979, that the N.H. & M.R.C. had similarly rejected an epidemiological study “Investigation of a possible association between the use of the herbicide 2,4,5-T and the incidence of neural tube defects in New South Wales” in December, 1978. This study, carried out by Dr B. Field and Professor C. Kerr of Sydney University had shown a direct correlation between 2,4,5-T usage and the incidence of neural tube defects in babies born in New South Wales from 1965 to 1976. A revised version was submitted to the Council early in 1979 but it was also rejected and the Council commented on May 24th, 1979:
“…the arguments it contained did not stand up to analysis because of serious deficiencies in statistical reasoning which created major doubts as to the validity of the conclusion reached.”
A summary of the report was published in The Lancet on June 23rd, 1979 (Field and Kerr, 1979) and this shows that the scientists were very cautious in drawing conclusions from their work. The method they used to gather and analyse data had previously been used to test and disprove Renwick’s theory that potato blight was causally associated with neural-tube defects without question. Further the scientists stated: “Our data and the record-linkage nature of analysis cannot be taken as direct evidence of any causal association involving 2,4,5-T”. The major point they made was that further retrospective analyses should be undertaken in other countries to throw some light on the significance of seasonal events in the origin of neural tube defects, and that the U.S. emergency suspension of 2,4,5-T provides a chance for a prospective trial in the Alsea area and elsewhere to see if the incidence of spontaneous abortions goes down after 2,4,5-T spraying ceases.
The action of the N.H. & M.R.C. in rejecting these two epidemiological studies so emphatically is puzzling as they have not publicly subjected any other studies on 2,4,5-T to such treatment. In the light of the Council’s abandonment of their cautious 1972 stand, the action must be viewed with alarm as their present stand will inevitably be interpreted as an endorsement of the safety of 2,4,5-T by many politicians, government authorities and industrialists.
Officials from the U.S. E.P.A. claimed in May, 1979, that they requested copies of the Field and Kerr report from the N.H. & M.R.C. but these requests had been refused. Allegations were also made that the N.H. & M.R.C. had attempted to stop the authors from publishing the report. The actions of the N.H. & M.R.C. over these reports prompt two questions - If the Field and Kerr report was so inconclusive, why not send copies to the U.S. E.P.A. with detailed comments? Also, has the N.H. & M.R.C. sent its apparently detailed and severe criticisms of the Alsea report to the U.S. E.P.A. for comment and clarification?
With regard to the N.H. & M.R.C.’s role throughout the 2,4,5-T debate we are left wondering:
1. What is the acceptable epidemiological study for the assessment of public health risk and has one been commissioned for populations exposed to 2,4,5-T?
2. What is an acceptable laboratory animal study for the assessment of health risks and has one been commissioned for 2,4,5-T?
3. What factor should be used to protect public health in the light of information obtained from such studies?
Government Enquiries into Birth Defect “Clusters” in Australasia
After reports about a relationship between birth defects and spraying with 2,4-D and 2,4,5-T in Vietnam were publicized, stories of “clusters” of birth defects in Australia and New Zealand started to emerge and an association with herbicide spraying was suggested for some. Two such “clusters” received heavy publicity and were investigated by government committees. The first was in the North Island of New Zealand (N.Z. Department of Health, 1977) and the second was at Yarram in South Gippsland (Consultative Council, Victoria, 1978).
The New Zealand enquiry actually covered three groups of clusters from 1974 to 1977, all in the North Island. The first group was from the Northland area where there were seven cases of neural tube defects, one in 1975 and six in 1976. The second group was from the Taranaki area where there were five cases of neural tube defects from 1974 to 1977 - four were from the town of Opunake, including three from one street. The third group was from the Waikato area where there were eight cases of neural tube defects in the four week period from 27th December, 1975 to 26th January, 1976.
If publicity had not been given to these clusters they would have passed unrecorded. In New Zealand the Department of Health has the responsibility for collecting full statistics on birth deformities. New Zealand Television revealed in March, 1977, that for Northland only one of the seven cases was recorded; and for Waikato none of the eight cases was recorded. This emphasizes why epidemiological studies on birth deformities have not yet yielded conclusive evidence on the risks associated with exposure to 2,4,5-T, even in developed nations the basic statistical data is unreliable. It also illustrates why reliable studies could not be carried out in Vietnam after the war ended.
The New Zealand Department of Health checked each individual case of a neural tube defect in the clusters, did some rough checks on spraying activities (mainly anecdotal) and exposure pathways and concluded in their report (June, 1977):
“In short, the data permit the conclusion that there is no evidence to implicate 2,4,5-T as a causal factor in human birth defects.”
Thus, although the clusters were real enough, epidemiological data was inadequate, no controls were used, and no causal factors were established; 2,4,5-T was positively rejected as a possible causal factor.
The Victorian enquiry concerned a cluster of neural tube defects at Yarram in the Shire of Alberton, Central Gippsland. Two local doctors reported three perinatal deaths related to neural tube defects among ninety three deliveries in 1975-76. Although the incident was reported to the Health Department no thorough investigation was performed. Finally, after newspaper publicity, a Consultative Council was established on 21st March 1978. The Council investigated the three perinatal deaths originally reported plus two additional cases of birth defects and two additional stillbirths which were brought to their attention.
At the outset, the Consultative Council noted that the requirements for documentation of birth deformities were inadequate and that in some cases where the child lives beyond 28 days there is no requirement to register details of birth abnormalities at all. Thus one of their two final recommendations was:
“The State should establish a unit to conduct research into the cause of birth defects with special emphasis on extra-genetic factors.”
The Council recognized the Yarram cluster was real, yet in spite of the above recommendation, they concluded that there was no evidence of a specific local cause and they dismissed 2,4-D and 2,4,5-T as possible causative factors.
The Statistical treatment of the Yarram data was most unsatisfactory. Firstly, the Council calculated that the probability of three perinatal deaths due to neural tube defects in ninety-three births was 1 in 500. This made the cluster appear highly significant, but the Council dismissed it. They reasoned that as there are about 60,000 births in Victoria each year and about 600 medical practices each delivering about 100 babies, it follows that a Yarram type “cluster” can be anticipated each year from one Victorian medical practice. No attempt was made to establish if this was in fact the case by retrospective analysis.
Next, the Council tabulated data for perinatal deaths and Lands Department usage of 2,4-D and 2,4,5-T for all Victorian statistical divisions for the years 1975 and 1976. They commented that the amounts of 2,4-D and 2,4,5-T used by the Lands Department “…generally reflect total usage of 2,4,5-T and 2,4-D within Victoria, however 2,4-D usage in cereal growing areas would be greater than indicated”. This assumption is not valid as these figures do not include the extensive usage of 2,4,5-T in forestry. In particular, the aerial spraying of the volatile ester of 2,4,5-T on the extensive publicly and privately owned pine plantations is not represented in the figures provided. This is critical in South Gippsland where the Forests Commission and Australian Paper Manufacturers have extensive pine plantations. Using Lands Department figures, the Council estimated total Victorian usage of 2,4,5-T was 23,081 kg in 1975 and 20,818 kg in 1976. The Forests Commission alone aerially sprayed an additional 2,375 kg in 1975 and 2,107 kg in 1976 - an extra 11%.
To statistically test the significance of the Yarram “cluster” which occurred in the Victorian statistical division with the highest usage of 2,4-D and 2,4,5-T, comparison was made to a statistical division with lower usage. The method used, however, was unacceptable. For analysis, the Yarram “cluster” data was lumped into data for the whole Central Gippsland division which is very heterogeneous, it includes for example, the dispersed rural farming south Gippsland population. Thus the Yarram data was confounded. Also, the perinatal death rate for the Central Gippsland division outside Yarram (mean 1.62%, 1975-76), is much lower than the rate for Yarram (mean 4.28%, 1975-76). Thus the Yarram “cluster” was diluted.
Having confounded and diluted the Yarram cluster, the Council then arbitrarily selected a statistical division with lower usage of 2,4-D and 2,4,5-T than Central Gippsland. They chose Loddon-Campaspe which was the division with the highest rate of perinatal deaths for the years 1975-76 (mean 2.17%). Thus the best possible example to disprove a causative link was selected. In addition, no attempt was made to establish that Central Gippsland and Loddon-Campaspe only differed in usage of the herbicides. Not surprisingly, analysis showed no significant difference in perinatal deaths between the two divisions. Having established to their satisfaction that there were no quantitative differences, the Council provided data for the two divisions to show that the birth deformities recorded were qualitatively similar. This analysis does not constitute a sound epidemiological study.
In the Consulatative Council’s Report (1978) the Yarram “clusters” are tabulated with data for Yarram District and figures are provided for the District from 1972 to 1977. For Yarram District, the perinatal death rate per 1,000 births was 49.5 in 1975 and 34.9 in 1976 with a mean of 42.8 for the two years. If this data is compared to that for Central Gippsland outside Yarram District and for all other Victorian statistical divisions, the Yarram rate stands out as very high. This is done in table 2, which shows the Yarram rate compared to that of Central Gippsland minus Yarram, to all of Victoria, to Northern Mallee (with Victoria’s lowest rate) and Loddon - Campaspe (with Victoria’s highest rate). Note that the Yarram District mean for 1975-76 (42.8) is 122% higher than the Victorian mean (19.2) and 164% higher than that for Central Gippsland minus Yarram District (16.2). Note also that the Yarram District Mean for 1972-77 (33.1) is 72% higher than the 1975-76 Victorian mean (19.2) and 96% higher than the 1975-76 mean for Central Gippsland minus Yarram District.
The Consulative Council’s report (1978) only analysed perinatal deaths, i.e. deaths from the 20th week of pregnancy to the first month after birth. 2,4,5-T is known to be embryotoxic in laboratory mammals (U.S. E.P.A., 1978). As a result of the U.S. E.P.A.’s Alsea study it is also thought to be an abortificant and cause miscarriages in women prior to the 20th week of pregnancy. The Council’s report provides data for the total number of births for the Yarram district from 1972-77 which shows a progressive decrease from 114 in 1972 to 73 in 1977 - a decline of 36%. A similar trend is evident for Alberton Shire from 1968 to 1977, there were 155 births in 1968 and this steadily decreased to 90 in 1977 - a decline of 42%. 1968 was the year in which the aerial spraying with the butyl ester of 2,4,5-T commenced, thus there could have been an increase in spontaneous abortions since this practice started as in Alsea, Oregon. Obviously this aspect needs careful study.
In addition to the above criticisms, the exposure risk analysis is also flawed. When extrapolating teratological data from laboratory animal tests to humans, the Council failed to use a factor and directly applied the no adverse effects level for rats and mice to humans. This factor must be at least 100 (N.H. & M.R.C., 1972; V.P.C., 1966) and should be 2,000 (U.S. E.P.A). Thus teratological exposure risks are all underestimated by a factor of 2,000.
In summary, the Consulative Council’s report underestimated total 2,4,5-T usage and completely overlooked the hazardous aerial application of the buytl ester in forestry; their epidemiological analysis was badly flawed; and they grossly underestimated the human teratologica risk from 2,4,5-T exposure.
The Council’s report cannot be taken as conclusive in any way and certainly does not rule out the possibility that the Yarram “cluster” in 1975-1976 were caused by 2,4-D or 2,4,5-T usage. Unfortunately, it is already being represented by some politicians and user groups as having cleared 2,4,5-T.
Debate on the dangers of 2,4,5-T is much wider than either a forestry or conservation issue. The dangers are immediate and involve public health, yet neither our forest managers or our public health guardians seem to be approaching the issue in a dispassionate or cautious way. A careful review of available facts coupled with realistic safety factors is essential for adequate protection of forests and human life.
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LEE, C., 1972. The monitoring of aerial spraying of herbicide. Research Activity 72. Forests Commission of Victoria: 43-44
MCKIMM, R.J., 1974. Herbicides monitoring in the forests environment. Research Activity 74. Forests Commission of Victoria: 47.
MCKIMM, J.J. and P.HOPMANS, 1977. Herbicide monitoring in the forest environment. Research Activity 77. Forests Commission of Victoria: 37.
MCKIMM, J.J. and P. HOPMANS, 1978. 2,4,5-T residues in stream water after aerial spraying in the Narbethong Plantation, Victoria. Aust. For. 41 (4): 215-222.
MCKINNELL., F.H. and T.B. BUTCHER, 1973. Weed Control in Radiata Pine Plantations. Bulletin No. 83. Forests Department of Western Australia: 1-23.
NATIONAL HEALTH AND MEDICAL RESEARCH COUNCIL, 1973 (a). Mehtylmercury in Fish: Effects on Human Health. Australian Government Publishing Service, Canberra: 1-10.
NATIONAL HEALTH AND MEDICAL RESEARCH COUNCIL, 1973 (b). Report of Seventy-Fifth Session, Canberra, November 1972. Australian Government Publishing Service, Canberra: 15.
NATIONAL HEALTH AND MEDICAL RESEARCH COUNCIL, 1975. Report of the Eightieth Session, Brisbane, April 1975. Australian Government Publishing Service, Canberra: 8-9.
NATIONAL HEALTH AND MEDICAL RESEARCH COUNCIL, 1978. Report of the Eighty-Fifth Session, Adelaide, June 1978. Australian Government Publishing Service, Canberra: 21.
NEW ZEALAND DEPARTMENT OF HEALTH, 1977. 2,4,5-T and Human Birth Defects. Division of Public Health, New Zealand Department of Health, June 1977: 1-43.
\PESTICIDES REVIEW COMMITTEE, 1978. Code of Practice for Large Scale Application of Pesticides in Victoria. Premier’s Department, Melbourne, December 1977 : 1-14.
RAMEL, C., 1978. Chlorinated Phenoxy Acides and their Dioxins. Ecol. Bull. (Stockholm) 27 :1-302.
STANDARDS ASSOCIATION OF AUSTRALIA, 1976. Herbicides of the Phenoxyacetic Acid Type. Australian Standard No. AS 1175-1976. S.A.A., North Sydney :1-52.
U.S. ENVIRONMENTAL PROTECTION AGENCY, 1978. Pesticide Programs: Rebuttable Presumption Against Registration of Pesticide Products Containing 2,4,5-T. Federal Register 43 (78) Friday, April 21, 1978 :17116-17157.
U.S. ENVIRONMENTAL PROTECTION AGENCY, 1979(a). Report of Assessment of a Field Investigation of Six-year Spontaneous Abortion Rates in Three Oregon Areas in Relation to Forest 2,4,5-T Spray Practices. Epidemiological Studies Program Human Effects Monitoring Branch, Washington, February 28, 1979 : 1-100.
U.S. ENVIRONMENTAL PROTECTION AGENCY, 1979 (b). Decision and Emergency Order Suspending Registrations for the Forest, Rights-of-Way, and Pasture Uses of 2,4,5-Trichlorophenoxyacetic Acid (2,4,5-T).U.S. E.P.A. Office of Pesticide Programs, Washington, February 28, 1979 : 1-110
U.S. ENVIRONMENTAL PROTECTION AGENCY, 1979 (c). Decision and Emergency Order Suspending Registrations for Certain uses of 2-(2,4,5-Trichlorophenoxy) Propionic Acid (Silvex).U.S. E.P.A. Office of Pesticide Programs, Washington, February 28, 1979 :1-102.
VICTORIAN CONSULATIVE COUNCIL, 1978. Report of the Consulative Council on Congenital Abnormalities in the Yarram District. Government Printer, Melbourne: 1-55.
VICTORIAN PESTICIDES COMMITTEE, 1966. Report of the Committee of Enquiry into the Effects of Pesticides. February, 1966. Government Printer, Melbourne :1-78.
WARNOCK, J.W. and J. LEWIS, 1978. The Other Face of 2,4-D: A Citizens’ Report. Penticton Commercial Printing Ltd., Penticton, British Columbia :1-165.
WHITESIDE, T., 1970. Defoliation. Ballantine Books., New York : 1-168.
WHITESIDE, T., 1977. A reporter at large: The pendulum and the toxic cloud. The New Yorker July 25, 1977 :30-55.
WORLD HEALTH ORGANISATION, 1972. Evaluation of Certain Food Additives and the Contaminants Mercury, Lead and Cadmium. Sixteenth Report of the Joint FAD/WHO Expert Committee on Food Additives.
W.H.O. Technical Report Series No. 505. U.N.Geneva: 1-32.
J.B Dargavel & M.J. Hall (APM Forests Pty Ltd).
P747: Sourced from Table 3:
Current Establishment Practices
Victoria (Government Forest Service): 45% of current planting areas from old farm and scrub land. 50% from natural forest and 5% second rotation pine.
Site Preparation: Forest: Plough. Grass: Rip.
Weed Control: Amitrole and Atrazine after planting.
Fertiliser (kg/ha): 7 kg/ha P
A.P.M Forests (Victoria): 33% of current planting areas from old farm and scrub land. 67% from natural forest.
Site Preparation: Plough and Mound.
Weed Control: Amitrole, Simazine, 22DPA and 2,4,5-T before and after planting.
Fertiliser (kg/ha): 100 kg/ha N, 100kg/ha P, 100 kg/ha K
P748: “Weed Control. The importance of weed control in the fast early development of plantations has been clearly demonstrated over many years in both countries. It is particularly important to remove competing vegetation in areas of Australia where moisture is limiting. This importance is heightened where fertilizers are used at establishment because the full effect of fertilization is often only obtained when weeds are well controlled.
Weed control, prior to planting, is generally achieved by cultivating the soil in the course of preparing the sites. Methods of controlling weeds after planting have been radically changed over the last 5 years as manual and mechanical methods have been almost entirely superseded by chemical control. Many new weedicides have become available and considerable research is in progress to determine formulations, and rates and methods of application, for forestry purposes.
Chemicals which are commonly applied to kill os “knock down” weeds include Picloram, 2,4,5-T, Amitrole and 22 DPA. The second two are tending to be used more as they are more effective and less hazardous. Chemicals commonly applied to bare soil to prevent the germination of weed seeds include the triazines, Simazine and Atrazine. The use of Glyphosate and Velpar which can also be used to knock down plants is being investigated (Cameron and Stokes 1977). . .
The main weedicides used in Australia and New Zealand:
Amitrole. 1.25-2.5 (Rates (kg/ha active ingredient). Before planting to knock down annual weed growth (Cameron 1977).
Atrazine & Amitrole. 3.0 0.3-0.8 kg/ha. Before and after planting along planting lines. Maintains weed-free conditions for 12 months (Woods 1976).
Picloram. Killing large trees by stem injection 5 ml 4% (ai) solution per 15 cm of girth (Jack 1968).
Simazine. 5-11 kg/ha. Before, at or after planting on weed-free soil. Maintains soil weed-free for 12 months (Cromer 1977, Cameron 1977).
22 DPA. 5-11 kg/ha. Heavy perennial grass control before planting (Cameron 1977). 2,4-D. 1-2 kg/ha. Control of herbaceous weeds (eg thistles, ragwort).
2,4,5-T 1-2 kg/ha. Total control of blackberry or selective control of woody weeds (eg eucalypt and acacia) in pine plantations (Preest 1977).
Some indicative results Woods (1976) compared frequent mowing with using weedicides to obtain weed free conditions for P.radiata. The biomass attained at age 3 years was 3.4 and 7.5 t/ha respectively.
De Boer (1970) found a height response of 52% over controls in P.radiata aged 2 years after application of atrazine and amitrole in grassland and in addition considerable improvement in both needle colour and survival.
Cameron (1977) showed that the duration of weed control was important in 4 experiments covering a range of Victorian sites.He found that stem volume at 2-3 years was increased by 25% when weeds were controlled for 1 year, but by 147% when they were controlled for 2 years. Cromer et al. (1977) compared the effects of fertilizers with and without weed control on the estimated cost of growing pulpwood taking into account losses in specific gravity due to early fast growth. Although weed control with triazines cost $A105/ha over 3 operations, the estimated costs of growing pulpwood over a rotation were reduced 26% by weed control. The fertilizer resulted in further reductions.
EARLY TENDING (5-10 YEARS) AND FERTILISTION AFTER THINNING.
Victoria: Weed Control 2,4,5-T. 77kg/ha P (Fertilisation between Planting and Thinning (kg/ha)). Other elements Zn.
APM Forests (Victoria): Weed Control: Slashing and Chemical. 59 kg/ha N, 24 kg/ha P, 187 kg/ha K (Fertilisation between Planting and Thinning (kg/ha)).
Permits granted to Victorian Plantations Corporation to Handle Protected Flora - under Flora and Fauna Guarantee Act 1988:
1. To gain approval for the Victorian Plantations Corporation to take protected flora for sale from public land.
2. The VPC are operating softwood plantations on public land.
3. Taking is only permitted within 2 metres of roadsides; during road formation, or during logging operations.
4. Tags must be attached to tree ferns at the time of taking. These tags will be issued by Regional Office of DNRE. Trade in tree ferns is not permitted unless each fern is tagged at the point of sale.
5. Harvesting of ferns in this way provides a local supply of ferns for the nursery trade. This is in addition to a large number of ferns imported from Tasmania.
Victorian Plantations Corporation (Yarram) - Permit 26/4/94 to 30/4/95 - 200 Soft Tree-ferns (Dicksonia antartica) & Rough Tree-fern (Cyathea australis) - Tag No's: 1249301 - 1249500. Ferns to be taken from areas being prepared for re-establishment of Pine plantations.
Victorian Plantations Corporation (Yarram) - Permit 12/7/94 to 12/7/95 - 1000 Mother Shield Ferns (Polystichum proliferum) - From Public land vested in the VPC (Latrobe Zone) and set aside for softwood (pine) production. No tags.
Victorian Plantations Corporation (Yarram) - Permit 20/7/95 to 10/7/96 - 500 Soft Tree Ferns (Dicksonia antartica) & Rough Tree ferns (Cyathea australis). Tag No's 750001 - 750500. 1 i) cutting areas within softwood plantations, in conjunction with harvesting operations. Ferns not to be taken from any areas of retained vegetation such as buffer zones, filter strips etc. ii) up to one (1) metre from the edge of permanent roads, firebreaks and access tracks. 2. Ferns not to be taken from hardwood plantations and associated areas of retained vegetation (such as buffer zones, filter strips etc).
Victorian Plantations Corporation (Yarram) - Permit 10/4/96 to 9/4/97 - 200 Soft Tree Ferns (Dicksonia antartica) & Rough Tree ferns (Cyathea australis). Tag No's 750651 - 750850.
Victorian Plantations Corporation (Yarram) - Permit 10/4/96 to 9/4/97 - 1000 Soft Tree Ferns (Dicksonia antartica) & Rough Tree ferns (Cyathea australis). Tag No's 753501 - 754000. 753001 - 753500.
Victorian Plantations Corporation (Yarram) - Permit 7/8/96 to 1/3/97 - 1000 Mother Shield Ferns (Polystichum proliferum) - From Public land vested in the VPC (Latrobe Zone) and set aside for softwood (pine) production. Tag No's 751501 - 752000. 752001 - 752500.
Victorian Plantations Corporation (Yarram) - Permit 26/5/97 to 26/5/98 - 1000 Mother Shield Ferns (Polystichum proliferum) - No Tags required. Ferns taken from; 1 i) cutting areas within softwood plantations, in conjunction with harvesting operations. Ferns not to be taken from any areas of retained vegetation such as buffer zones, filter strips etc. ii) up to one (1) metre from the edge of permanent roads, firebreaks and access tracks. 2. Ferns not to be taken from hardwood plantations and associated areas of retained vegetation (such as buffer zones, filter strips etc).
Victorian Plantations Corporation (Yarram) - Permit 26/5/97 to 26/5/98 - 1200 Soft Tree Ferns (Dicksonia antartica) & Rough Tree ferns (Cyathea australis). From i) Softwood plantations within the Latrobe Zone. ii) to one (1) metre from the edge of permanent roads, fire breaks and access tracks within the Latrobe Zone. Tag No's 1260501 - 1261700. Ferns taken from; 1 i) cutting areas within softwood plantations, in conjunction with harvesting operations. Ferns not to be taken from any areas of retained vegetation such as buffer zones, filter strips etc. ii) up to one (1) metre from the edge of permanent roads, firebreaks and access tracks. 2. Ferns not to be taken from hardwood plantations and associated areas of retained vegetation (such as buffer zones, filter strips etc).
Victorian Plantations Corporation (Yarram) - Permit ? to 18/7/98 - 2000 Fishbone Water Fern (Blechnum nudum). No Tags Required - To two (2) metres from the edge of permanent roads, fire breaks and access tracks within the Latrobe Zone.
Victorian Plantations Corporation (Mirboo North) - Permit 23/9/98 to 25/9/99 - 400 Mother Shield Ferns (Polystichum proliferum) - No Tags required.
Victorian Plantations Corporation (Mirboo North) - Permit 4/11/98 to 25/9/99 - 800 Rough Tree-fern (Cyathea australis) & Smooth Tree-ferns (Dicksonia Antarctica). Tag No's: 97501 to 98250 750 tags and 96801 to 96850 50 tags = total 800 tags.
DISCUSSION PAPER OCTOBER 1982
FORESTS COMMISSION VICTORIA
P3 “P. radiata was first collected in the Perouse Expedition of the 1780’s but not adequately described until 1837 from specimens collected in 1829. The first record of it in cultivation was 1833. A few plants may have been brought into Australia in the 1840’s or 1850’s but the first firm record is of a batch of seed for Melbourne and Sydney Botanic Gardens via the “Duncan Dunbar” which berthed at Sydney on 13 December 1857. There is no evidence to support the rather romantic legend that it was brought to Australia by the “forty-niners” of California migrating to the local gold-fields.
From about 1860 Baron von Mueller, then Director of Melbourne Botanic Gardens distributed plants very widely to landowners and it rapidly established itself as a fast growing hardy tree adaptable to a wide range of sites. It was introduced to South Australia in 1866 and to Tasmania a few years later.
Although Mueller first suggested planting it in plantations in 1866, the first plantations were established at Macedon in 1880, Creswick 1888 and You Yangs 1889. These sites represented high medium and low rainfall areas. Little further planting took place until 1910. By this time P.radiata had established a reputation for “growing anywhere” and as there were large areas of coastal land unsuitable for agriculture several projects were commenced. The main ones were Frankston 1910, French Island 1911, Wilsons Promontory 1913, Port Campbell 1919, Anglesea 1923, and Mt Difficult 1925. Some 11,000 ha were planted but most failed and only about 140 ha remain today. A small plantation of 35 ha on dredge tailings following gold mining was planted at Bright in 1916 and one on grantite country at Harcourt in 1910. Pine planting was regarded as a very effective way of rehabilitating and improving the aesthetics of mined and sluiced land.
By the late 1920’s it appeared that coastal sands were largely unsatisfactory and planting of the poorer foothill country was begun (Scarsdale and Myrtleford) in 1927. With the provision of Unemployed Relief Funds during the Depression, the main existing plantations (Macedon, Creswick, Scarsdale, Bright and Myrtelford) were expanded and new projects commenced at Beechworth and Beech Forest in 1930, Narbethong 1931, and Neerim 1933. By the end of the Relief Funds in 1938, total plantation area was about 18,000 ha.
During the latter part of the 1920’s bond selling companies were very active and substantial areas were planted privately in the south-western districts. They were also active in adjoining areas of South Australia. Planting in SA was also increased and while many thousands of hectares subsequently failed, sufficient were satisfactory to start the present softwood industry. A royal Commission in SA in the late 1920’s determined that an annual planting rate of 1,200 ha was warranted and this program continued until the 1960’s.
In the 1939 fires Narbethong and Neerim plantations were largely destroyed plus about two thirds of Bright plantations; total loss being about 4,400 ha.
Planting virtually ceased during the war years but resumed in 1945 with an annual target of 2,000 ha. Because of numerous shortfalls this was not reached until 1949 only to be cut back to less than 200 ha with the reductions in loan funds of 1951 -52. Noteworthy for this brief period of expansion was the start of two new major projects, the South-Gippsland Reforestation Scheme in 1945 and Rennick in 1947 . . . The South Gippsland scheme was started, inter alia, to rehabilitate abandoned farmlands and to control noxious weeds.
Annual plantings were less than 400 ha during the 1950’s until the pine plantation expansion (PX) program commenced in 1961. Annual target was 2,000 ha and was reached in 1964.
The First Commonwealth-States Softwood Forestry Agreement of five years term was ratified in 1966 with Victoria’s planting program being planned to reach 6,000 ha by 1971. However in the late 1960’s some slowing up occurred and peak planting was 4,800 ha in 1971. A second Agreement to 1976 was ratified which continued annual planting at 4,000 ha after which it has declined to around 3,000 ha. Total Commission softwood area established at 30 March 1982 is 89,900 ha of which 92 per cent is P.radiata. . .
P7 PLANTATION DEVELOPMENT ZONES IN VICTORIA
Rationale for Zones
The eight softwood development zones were defined in the early 1960’s when the decision to greatly expand the softwood plantation area in all States were taken. This policy aimed at net domestic self-sufficiency. The Victorian contribution was to be distributed across the region of the State which has suitable land and climate for radiata pine in a manner designed to promote decentralized development. The initial aim was to provide a sufficient resource to sustain a self-contained suite of industries in each zone. The location of the zones within the broad region that is neither too dry nor too high and cold was based on existing nuclei of older plantations. This was the case in the Ovens, Central, Latrobe, Ballarat, Otways and Rennick Zones. Surveys were undertaken to determine suitability and it was established that in each zone there was an adequate area of public and freehold land. The general objectives of the scheme were strongly supported by local communities and there was active lobbying by municipalities to participate. The additional zones of Benalla/Mansfield and Upper Murray were established at that time.
The expansion of State plantings was followed by increases in freehold plantings and together they now provide a resource which is enabling industries to expand and new industries to establish. . .
Private Property Purchases
The Commission has over the past fifty years purchased about 100,000 hectares of private property and returned it to the forest estate. Most of the land was marginal or unsuitable for agriculture and it was often in need of rehabilitation by afforestation. This has required a sustained effort since funds have never been readily available for this purpose. . .
P 13 Private Softwood Plantations
. . . The larger holdings representing 75% of the private resource is vested in three companies - APM Forests Pty Ltd, Southern Australia Perpetual Forests Ltd (SAPFOR) and Softwood Holdings Limited. The largest project is that of APM Forests with a plantation area of 40,500 ha in central and south Gippsland established over the past 30 years to supply part of the needs of its processing plants in the Latrobe Valley.
The other two companies are based in South Australia and have a total plantation area of 21,960 ha in south-west Victoria on both freehold and public land. SAPFOR commenced operations in the late 1920’s and is the chief company involved in investment forestry in Australia. More than half the total area of plantation established by SAPFOR in Victoria is on public land made available under the provisions of the Land (Plantations Areas Act) 1966.
Softwood Holdings with an area of 8,300 ha has established the majority of its plantations on company owned land and a smaller area on leased public land to supply its processing plants in South Australia and also at Portland.
The third largest area under private ownership is in the Otways where several companies associated with the timber industry in the Colac area have been pursuing planting programs since 1972. A substantial area has also been established in this period by Smorgon Consolidated Industries Pty Ltd.
The Government has encouraged private investment in softwood plantations in various ways. The leasing of public land for plantation development is well established with a total of 22,000 ha made available. A further 7,700 ha of softwood plantations have been established on private land with Government assistance through the Farm Forestry Loan Scheme.
In 1959 the passing of the Land (Plantation Areas) Act enabled private individuals and companies to obtain a long-term lease with provision for ultimate freeholding of Crown Land for commercial tree planting. A total of 14 such leases over 13,350 ha have been granted to four companies for the planting of Pinus radiata. . .P17 FOREST COMMISSION PRACTICES FOR ESTABLISHING SOFTWOOD PLANTATIONS (see copy of Standing Instruction M-105)
. . . There are three basic categories of land involved in the establishment of softwood plantations. These categories based on vegetation cover are native forest land, scrub-covered land, and grass land usually associated with some tree cover.
For satisfactory growth of radiata pine on these lands average rainfall should exceed 650 mm, soils must be reasonably fertile and well drained or capable of improvement by applying fertilizer and/or appropriate site preparation. Steep topography is generally avoided, particularly on unstable soils of where the plantations are to be thinned during the rotation. Plantations to be commercially thinned prior to final felling are usually confined to slopes not generally in excess of 20 degrees. Except for clearing scrub lands on stable soils in the hilly country of the Strzelecki Ranges practically all clearing for new plantations is undertaken on topography ranging from flat to slopes not generally exceeding 20 degrees.
Bulldozers are used in clearing native forests. Machines may work independently, or in teams directly pushing standing trees, or in teams employing the technique called chaining. The latter involves attaching a heavy anchor chain about 90 metres in length between two large bulldozers. The machines work in parallel paths about 50 metres apart with the chain looping behind and pulling down trees as the machines progress. A third, or chaser machine fitted with a tree pusher may follow the chain to assist with the more stubborn trees. After felling, the debris is heaped into windrows some 30 m to 40 m apart orientated on flat and moderately sloping ground to best suit later extraction of plantation thinnings. Where slopes exceed 13 degrees, windrows are usually aligned to closely follow the contour. After heaping a final root raking cleans the site of remaining debris and roughly levels the ground for subsequent ploughing, ripping, or machine planting. The windrows of debris are burnt when conditions are safe but conducive to a hot fire to remove as much of the heavy trunk wood as possible.
On the dense scrub covered sites of the Strzelecki Ranges, bulldozers usually work in pairs clearing as wide an area as possible before depositing debris at the end of each clearing run. Slopes in excess of 30 degrees in this hilly country may be cleared for plantation establishment.
In lightly timbered grass land country a bulldozer is used to fell standing trees and push debris into relatively small and scattered heaps.
Following clearing additional site preparation, usually in the form of ploughing, ripping, or both according to site requirements, may be undertaken. Where topography and ground surface conditions are suitable most cleared native forest sites are ploughed, the major objective being to chop and expose to the surface live wattle roots and eucalypt lignotubers which, if left undisturbed, regenerate rapidly and compete seriously with the establishing pines. Although ploughing is not totally effective it significantly delays the return of competing vegetation. Ploughing is undertaken with heavy duty off-set disc, stump jump disc, or blade type ploughing equipment. On flat poorly drained sites mound ploughing, may be undertaken to enable planting on raised ground above the level of water logging.
Ripping is undertaken on most grass land sites, cleared scrub land sites, and some heavy clay soil areas. Single rips are prepared along the lines to be planted, these being along the contour on steep slopes. The ripping enhances early plant establishment by assisting drainage on wet sites, by fracturing heavy soils aiding young root development, and by conserving moisture in the rip line on drier sites. Ripping is normally to 30 cm depth, but where an impervious layer exists close to the surface deeper ripping to 60 cm or more is required.
For clearing and site preparation the Forest Commission uses both departmental and contract plant. In recent years clearing programs have been between 2,700 ha and 3,200 ha annually with about 55% being done departmentally and the balance by contractors.
The cost of preparing land to a condition suitable for planting varies considerably according to the difficulty of clearing. In 1982 felling, heaping and windrowing of relatively light timber growing on sandy soils costs about $150 per hectare, but the clearing of heavy timber growing on undulating to steep country may cost in excess of $380 per hectare. Ploughing costs range between $35 and $70 per hectare according to type of country and weight and size of equipment used, while ripping costs are generally of the order of $45 to $50 per hectare. Clearing costs in steep scrub covered country may exceed $300 per hectare.
Burning of heaped and windrowed debris is undertaken in late autumn when risk of fire escape is low. Although stoking to complete the burning of windrows would facilitate planting and later utilization of produce this is not done because of the high cost involved.
Planting stock from the Commission’s Regional Nurseries becomes available in May following nursery hardening off procedures of root pruning and top pruning, and, for inland nurseries, exposure to frost. Field planting is commenced when soils are sufficiently moist and according to seasonal conditions the period available usually extends from late May through to the end of August.
After many years of establishment planting at 2.4 m x 2.4 m (1700 plants per ha), espacement now is 3.0 m x 2.4 m (1360 plants per ha) for sites likely to be thinned, and 3.0 m x 3.0 m (1000 plants per ha) for sites not likely to be thinned. Wide espacement has become possible through increased survival resulting from improved quality planting stock and better site preparation. It provides also for economies to be effected in establishment cost, and for the growing of fewer but larger diameter trees - a fact which has important implications for the stability of the stand and the economics of harvesting operations, particularly first thinning.
Planting is carried out by crews using spades or mattocks as planting tools, and in the case of some large expanses of generally flat and gently sloping land tractor drawn machine planters are used.
Following planting and over the next several years there are two major tending requirements likely to be needed. These are either or both of control of competing weeds and of fertilizer application to achieve satisfactory plantation growth. The major weed competitors in plantations are grasses, where pastureland was planted, and woody weeds - mainly eucalypts, wattle, dogwood and other scrub species on cleared native forests and scrub land sites. On pastureland grass must be controlled shortly after planting to ensure plant survival through their first summer. The most common treatment for this is to strip spray amitrole-atrazine herbicide mixture along planted lines either by hand held spray equipment or tractor mounted boom spray.
Amitrole has a knock down effect on standing grass while atrazine largely inhibits new germination for a period of several months. The release achieved provides for good early pine growth and follow up treatment is usually not required in the second year except for a few sites where there may be a prolific return of grass growth. The cost of spraying for grass control is of the order of $55 per hectare.
The control of woody weeds in plantations is much more difficult and expensive. If weeds are allowed to gain full site occupancy the growth potential of pine is very seriously reduced. Where eucalypts and silver wattle in particular are involved their development is rapid and they can quickly overlap the pines, which could result in plantation failure if not controlled. Woody weeds may be kept in check by manual slashing but as eucalypts and silver wattle reshoot vigorously after cutting the treatment may have to be repeated two or three times.
Because of the cost of repeated treatments, a limited labour resource for the work, and the extent and physical difficulties of the total area in need of treatment, other means for cost efficient control must be adopted over a large part of the planted area. On dense weed sites aerial spraying with herbicides is the most cost effective treatment especially if weeds are treated when young and in a condition susceptible to control at low application rates of chemical.
Aerial spraying is carried out by fixed wing aircraft or helicopter but helicopter is preferred because of its ability to direct spray material more precisely and effectively to the target area.
Herbicides of low volatility and toxicity are currently being used with application costs ranging from $150 per ha for treating young weed growth to over $250 per ha for controlling older weeds at a higher application rate of chemical. The cost for manual cutting on these site types would range from $200 to over $500 per hectare with the requirement for two or three repeated treatments. With herbicide treatment, providing application rate requirements are correctly assessed, there is only limited requirement for follow-up work.
The most significant soil mineral deficiency for plantation growth on many Victorian soils is phosphorous, and where levels are critically low supplementation with phosphate fertilizer is necessary. On such sites a spot application with super-phosphate at 180 gm per tree is made soon after planting time to boost early growth, which should be followed some five years later with an aerial broadcast application. The cost of material and aircraft for application is of the order of $110 to $120 per hectare.
For some soils, particularly the poor sands of south-western Victoria, both weeds control and fertilizer treatment soon after the time of planting are essential to ensure plantation establishment. Generally, because of previous fertilizing history, pastureland sites do not require superphosphate at the time of planting . . .
Where rainfall is adequate, growth rates on poor or marginal sites can often be substantially improved by fertilizer application. Phosphate is normally the limiting nutrient for pine growth in Victoria and the application of phosphatic fertilizers on sites deficient in this nutrient commonly produces a 25-30% increase in growth rates. Application is usually done by hand at time of planting, and by aerial application in later years.
On some soils, trace element deficiencies, eg. Zinc, copper or boron, can cause severe growth problems. Applications of very small amounts of these elements can give dramatic increases in tree health and vigour.
Fertilizer application is an accepted practice on sites of lower productivity in Victoria, but is generally unnecessary on better sites.
Rotation and Timber Yields
Most radiata pine plantations in Victoria are managed on the basis of a 30 to 35 year rotation, with 2 or 3 production thinnings. A very limited amount of non-commercial thinning is undertaken. Where thinning is delayed due to lack of a suitable market, for the produce, or difficulty and cost of harvesting, the stand may become progressively unstable or suffer excessive mortality. In such cases it may be necessary to consider clear felling the stand earlier than planned - often between 28 to 30 years.
An indication of the approximate yields and products from a typical Victorian plantation of medium site quality is as follows:
First Thinning: Approx 80m3/ha - mainly pulpwood and round timber for preservation
Second Thinning: Approx 80m3/ha - about 50% pulpwood, 50% sawlogs.
Third Thinning: Approx 130m3/ha - about 25% pulpwood, 75% sawlogs.
Clear felling: Approx 330m3/ha - about 10% pulpwood, 90% sawlogs and veneer logs.
The conversion of native eucalypt forest to radiata pine can affect a number of hydrologic processes, such as interception, infiltration, overland flow and evapo-transpiration, all of which influence streamflow behaviour and streamwater quality. This has been the subject of a considerable and continuing research effort in Australia, with the Forests Commission Victoria actively involved.
Streamflow characteristics, such as baseflow and stormflow have generally been shown to increase following clearing due to a reduction in transpiration and interception respectively. Infiltration rates may be adversely affected with a consequent increase in overland flow and hence peak stormflows. As the pine plantation develops and canopy closure occurs, there is a gradual reversal in streamflow behaviour whereupon both baseflow and streamflow are less that that prior to clearing of the mature eucalypt forest. This has been found in a number of instances over a diversity of sites and is primarily related to differences in interception, with interception loss 8-10% higher from radiata pine foliage than from eucalypt due to a higher leaf area. Annual transpiration losses, from both radiata pine and eucalypt, have been found to be quite similar, though differences in seasonal patterns are evident. Thus it would be expected that converting native eucalypt forest to radiata pine can decrease water yields over portion of the rotation, unless thinning regimes are adopted to reduce interception losses.
Streamwater quality may be adversely affected as a result of road construction, soil disturbance due to clearing, ploughing and harvesting, and the use of fertilizer and pesticides. However, any deterioration in streamwater quality can be generally minimized to non-significant levels by careful management of these plantation forestry operations/ For example, the construction and maintenance of roads needs to be strictly controlled, especially at vulnerable points such as stream crossings and culverts. Poor roading can cause long-term deterioration of streamwater quality. Buffer strips are essential along the perennial length of streams so that any sediment and nutrients in overland flow are trapped before entering the stream system. On sites where soils are highly erodible logging should be restricted to the summer months.
Where fertilizer and pesticides are broadcast applied, strict control is necessary to ensure that the buffer strip and stream system is not treated during their application. Consideration of these factors in combination with prevailing site and climatic conditions should ensure minimal impact on streamwater quality.
INSECT AND FUNGAL ATTACK, STORM DAMAGE AND FIRE DAMAGE IN PINUS RADIATA PLANTATIONS AND THEIR CONTROL
The ecologically simple monocultures of radiata pine have largely remained free of significant damage by insects. This has occurred despite the adaption to pine of 11 species of indigenous defoliators, four species of indigenous lower stem/root borers, and the establishment in plantations of three introduced bark borers and of two wood borers.
The European wood wasp Sirex noctilio is presently the principal tree-killing pest in the major pine growing areas of the State. The wasp is attracted to trees that are suppressed, drought-stressed, nutritionally deprived, or otherwise weakened. Recently killed trees, green logs, green stumps and large green logging residues are also susceptible. Attack on pine occurs mostly between mid and later summer, when soil moisture levels, growth rates and tolerance of pine to pests and diseases are low. The attacked trees normally die within a few weeks, as a result of the activity of injected toxic mucus and a fungal desiccant. The wood of the killed trees is degraded and is rendered unacceptable even as pulpwood.
In southern Victoria, many valuable shelterbelts on farmland have been destroyed, especially during the 1960’s. Near Mansfield, about 25% of a 1906 ha plantation was severely damaged during the 1970’s. These unthinned stands of intermediate age incurred over 70% tree mortality, and merchantable wood volumes were reduced by 48% over a seven years period. Near Beechworth, a total of 300 ha of 13 to 17-year-old plantations were damaged during the late 1970’s, and some patches incurred 30% mortality.
Control by means of biological agents was practiced during the 1960’s and 1970’s but it has not always been satisfactory. A new technique for containing the wasp in unthinned plantations of intermediate age is being used this year in north-eastern Victoria. The technique consists of establishing a network of ‘trap’ trees throughout susceptible plantations, by injecting selected trees with herbicide. This treatment attracts wasps from considerable distances, and concentrates attack on ‘trap’ trees. These are then felled and inoculated with nematode parasites to render the emerging females wasps sterile, and so to prevent a population build-up in the next generation of Sirex.
The North American bark beetle Ips grandicollis, which invaded south-western Victoria from South Australia probably during 1980-81, is the only other tree-killing pest causing concern. Ips has a high reproductive capacity, and can produce up to four generations between spring and autumn. Some adults of the ‘late autumn’ generation produce a ‘winter’ generation, but most adults over-winter below the bark of slash or killed trees until spring, when attack on fresh slash resumes. When such material is not available, reproduction cannot occur, and beetle emergents perish. Outbreaks within plantations are therefore of short duration.
Between spring and autumn, green slash, freshly felled trees, wind-thrown trees, and those damaged by lightning strikes, may sustain ‘breeding’ attacks and/or ‘feeding’ attacks. Also susceptible to attack are nearby good quality trees of variable size and age. In a ‘breeding’ attack, larvae are the major destructive agents, whereas in a ‘feeding’ attack large swarms of beetles rapidly kill host trees by destroying stem phloem and cambium.
Although Ips is now widely distributed in Rennick and Heywood Forest Districts, only few trees have so far died from Ips attack. However, a hazardous situation may arise, especially in peripheral rows of 4 to 12-year-old, drought-stressed plantations, which are located close to clear-felled or thinned areas carrying large quantities of Ips-infested green or semi-green slash.
The burning of infested slash during autumn to destroy the overwintering adults, as well as early thinning of stands to improve tree vigour and to reduce the adverse effects of drought, have been recommended for containing a pest. On the sandy soils near Rennick, slash-burning is inappropriate, as it would seriously deplete the nutrient levels of the soil, and thus cause a second rotation problem. An alternative control strategy that will be evaluated in the near future involves trapping the adults by means of chemical attractants (pheromones), and where possible some modification in silvicultural practices. This research will be complementary to South Australian studies on the efficiacy of introduced beetle predators and wasp parasitoids in containing Ips.
Pine seedlings in nurseries are often affected by fungi causing disease, the most common being species of Fusarium (injuring roots), species of Pythium (causing damping-off), as well as Phytophthora cinnamomi, causing seedling deaths by injuring roots.
Phytophthora cinnamomi has also killed seedlings during the establishment phase in the field. Another important primary pathogen in plantations is Diplodia pinea. This fungus causes ‘dead topping’, defoliation, blue staining of the wood, malformation in stems and branches and occasionally tree death. Damage is most severe on trees injured by hail, or which have been drought-stressed, especially on marginal sites. Lophodermium pinastri and Naemacyclus niveus are widespread needle case pathogens, but damage so far has been slight.
Potentially the most important needle cast fungus in pine is Dothistroma septospora, which was discovered in Tallangatta Forest District in 1979. This pathogen kills needles and serious attack involves waves of defoliation each growing season, and this may severely reduce height and diameter increment and occasionally cause tree death especially of young trees. Traces of the pathogen have also been found in Beechworth and Bright Forest Districts. The fungus is being closely monitored in the outbreak areas. A comprehensive review of the fungus has been prepared to assist field foresters in the early detection of the disease, especially in areas where rainfall is high during the growing season.
A small amount of wind damage occurs in most plantations every year. The forces of sustained, gusty, high velocity winds either cause stem breakage, or more commonly, uproot the trees. The wood of affected trees usually becomes degraded by blue stain fungi, unless the trees retain some functioning roots, which keep foliage and cambium alive. In order to reduce such degrade, the trees need to be salvaged within a few months.
Tall and slender trees of intermediate age, ie. Those with a high height: diameter ratio and growing on wet soils in recently thinned stands, are especially prone to windthrow. On the contrary, trees which grow in relative isolation, or along roadsides, fire breaks and along plantation margins, generally have superior windfirmness, despite their large crowns and greater exposure.
The most extensive damage by wind and snow in recent years occurred in the Ovens Valley Group of Plantations during winter 1981. In Beechworth Forest District alone, the wood volume of uprooted trees amounted to 38,000 m3. Trees older than 18 years were salvaged by chain saw and tractor logging, whereas all younger trees were salvaged with ‘ANM Kockum’ systems. Operations were completed before the onset of significant blue staining and excessive drying of the wood, which would have rendered the material unacceptable as pulpwood. The current Commission policy is to plant only about 1000 trees/ha on high quality sites, to enable the trees to become windfirm at an early age, and to obviate the need for heavy first thinning.
Pines are fire sensitive and the potential for loss of wood volume from fire damage is high in plantations. The extent of loss is determined by fire intensity and the feasibility of salvage, both factors being dependent upon stand age. The worst situation arises at about first thinning age (12-15 years), when the combination of a very hazardous fuel distribution and small tree sizes can result in total loss, even under conditions of relatively low fire danger. As at March 1982, about 73% of plantations managed by the Commission were aged 15 years or less, implying that large plantation areas are presently very susceptible to damage by fire. The nature of the plantations, with their extensive areas of contiguous even-aged blocks, is another factor contributing to the potential for substantial loss from a major fire.
During the last decade, 50 fires have occurred in the Commission’s plantations, and this frequency corresponds to about one fire each year for every 18,000 ha of plantation. Forty-seven of these fires each damaged an area of less than 4 ha. The most destructive fires occurred near Creswick and Rennick in 1977 and 1979 respectively. In the Creswick fire, 258 ha of mature-age plantation, containing 218 ha of P. radiata and 40 ha of P.nigra, were killed, but most of the trees were salvaged. The Rennick fire originated in South Australia, and after burning about 3,300 ha of plantation in that State, burnt an additional 163 ha of 13-year-old P.radiata in Victoria. Only small volumes of burnt trees could be salvaged.
Extensive measures are taken to protect softwood plantations from fire. These measures include the provision of a well trained and equipped fire suppression force, the adoption of fuel management in the form of fuel reduction burning in adjacent native forest areas, and the provision of mineral earth boundary fire-breaks. Good access is maintained together with adequate water supplies for fire suppression. Hazardous fuel distributions are being reduced by means of mechanical methods (such as pruning) and low intensity controlled burning.