THE USE OF CHEMICALS TO RELEASE WHITE PINE REPRODUCTION

Transcription

1 CANADA Department of Northern Affairs and National Resources FORESTRY BRANCH THE USE OF CHEMICALS TO RELEASE WHITE PINE REPRODUCTION by E. S. Atkins THIS FILE COpy MUST 8E RETURNED TO: INFORMATION SECTION, NORTHERN FOREST RESEARCH CENTRE, STREET, EDMONTON, Al.BERTA. T6H 3S5 Forest Research Division Technical Note No

2 Published under the authority of The Minister of Northern Mairs and National Resources Ottawa, 1956

3 CONTENTS INTRODUCTION THE PROBLEM METHODS AND MATERIALS Results from Other Work Design of the Petawawa Experiments RESULTS... 5 Foliage Sprays Stump Sprays DISCUSSION AND CONCLUSIONS SUMMARy... 7 REFERENCES PAGE

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5 The Use of Chemicals to Release White Pine Reproduction by E. S. Atkins 1 INTRODUCTION At the Petawawa Forest Experiment Station, Chalk River, Ontario, white pine (Pinus strobus L.) seeds-in readily but development of the seedlings is often retarded by underbrush or other tree species. It is possible for white pine seedlings to remain suppressed for more than two decades unless release measures are taken. This is a problem common to many forest areas, differing mainly with the region and species involved. Where these situations exist, an inexpensive method of release would be of considerable economic value. Both height growth and vigor of the reproduction would be stimulated, thus assuring a new stand without delay once the existing overstory is harvested. In recent years, certain selective herbicides have been developed which offer considerable promise in releasing suppressed coniferous reproduction from competing shrubs. To foresters confronted with this silvicultural problem, the use of such chemicals may prove equally effective, but less costly, than the conventional removal of shrubs by hand methods. A study was therefore undertaken at the Petawawa Station in to test the selectivity of certain chemicals and their efficacy in releasing pine reproduction. Several herbicides were tested in different concentrations to determine which combinations would prove toxic to competing species but harmless to white pine reproduction. THE PROBLEM The Petawawa Forest Experiment Station lies in the L4 Section of the Great Lakes-St. Lawrence Region (3). Some 98 square miles of glacial till and outwash sand are enclosed by the Station boundaries. The forests on the area are typical of those found in the Upper Ottawa Valley. About 65 per cent of the area at Petawawa supports pine, either in pure form or in association with other species. Of the pines native to the area, white pine is by far the most important and widespread. One of the most important timber types is white birch-aspen-pine (Betula papyriera, Populus tremuloides and P. grandidentata, Pinus strobus, P. resinosa and P. banksiana). In this type, perpetuating the pine species is a silvicultural problem. Abundant white pine seed is released and germination is usually good. However, most of the seedlings survive for only a short period or remain very suppressed because of competition from established species. The unfavourable environment is often caused, at least in part, by the prevalence of hazel (Corylus cornuta) underbrush. Also, if the aspen is removed from the main stand, numerous root suckers of this species may invade the site within a short time. Release of the white pine reproduction from both hazel and aspen suckers is therefore required in such cases. 1 Formerly silviculturist at Petawawa Forest Experiment Station, now research loreeter, Alberta District Office, Calgary, Alberta. 3

6 Results From Other Work METHODS AND MATERIALS Bibliographies are available covering the extensive literature published on the subect of herbicides. For this reason, only a limited number of references on specific points of interest are given here. Three general methods of application have been developed which permit spraying with chemicals in both dormant and growing seasons. These are foliage sprays, basal bark sprays, and cut stump sprays. Of the three, foliage sprays have gained wider use in eradication of underbrush because bark treatments require a high concentration and are therefore expensive; cut stump sprays have the same disadvantage and considerable waste would accompany their use on very small diameters. Release of reproduction, preparation for a seed cutting, and eradication of brush along roadsides are typical problems where foliage sprays may be used to advantage. Conclusive results have been obtained elsewhere on certain aspects of foliage spraying, particularly time of year, air temperature, effect of increasing concentrations, and differences between amine and ester solutions. Results have been most effective when spraying was carried out during the period June to August. Temperatures over 65 F. were recommended by Ahlgreen, Klingman, and Wolf (1); apparently toxicity is lowered considerably at 50 F. or less. Zehngraff and von Bargen (7) tested high concentrations in a low volume of water as opposed to low concentrations in a higher volume of water. Control was much better with the latter combination. Suggitt (6) concluded from his experiments that there is a limit of concentration, around 3,500 p.p.m. (parts per million), beyond which no appreciable increase in effectiveness is gained. The Ontario Department of Agriculture (4) has recommended ester solutions as being more effective than sodium or amine solutions especially under unfavourable conditions. All investigators have stressed the need for thorough coverage of foliage. Design o the Petawawa Experiments On the basis of existing information, it was decided to test foliage sprays using water as a carrier, on hazel, aspen root suckers, and coniferous reproduction (particularly white pine), and to note the effects on other species such as red maple (Acer rubrum) which might occur on the treated area. A secondary experiment was also carried out on the treatment of aspen stumps to prevent root suckering. It has been pointed out that thorough coverage is essential in foliage sprays. As underbrush is rarely uniform in density, it is unpractical to adopt quantity per acre as a criterion which could be replicated. The "dripping point" was therefore accepted as a standard in the work at Petawawa. In other words, all foliage was sprayed thoroughly until the solution began to run off the needles or leaves. Four chemicals were selected for foliage treatments, as follows: Formula 40 (2, 4-D amine) Esteron 44 (2, 4-D ester) Esteron 245 (2,4, 5-T) Esteron Brush Killer (2, 4-D plus 2, 4, 5-T) 4

7 As a concentration of 1,000 p.p.m. is regarded by the manufacturers as being very weak, the above chemicals were tested in three concentrations-1,000, 3,000, and 5,000 p.p.m. 2 These low concentrations were selected because of the possibility of inuring coniferous reproduction with higher proportions of herbicide. An area was then selected supporting an overstory of white and red pine with minor proportions of white birch and aspen. Patches of hazel were quite numerous, with white pine reproduction ranging from one to two feet in height and 10 to 20 years of age, growing among the hazel. In August, 1951, two series of 12 mil acre quadrats, containing both hazel and pine reproduction, were established and sprayed with each chemical and concentration. This replication of four chemicals and three concentrations resulted in a total of 24 treated quadrats. For a further assessment of the effect of the chemicals on coniferous reproduction, individual white pine, red pine, and white spruce (Picea glauca), from one to three feet in height, were also sprayed. Six trees of each species were treated, using three chemicals and two concentrations (Esteron Brush Killer and concentrations of 5,000 p.p.m. were omitted). To complete the experiment on foliage sprays, a second area was chosen with aspen root suckers and red maple sprouts, both of which were two years of age. The design of treatment was identical to that described above for hazel-four chemicals and three concentrations on milacre quadrats, with two replicates. In addition to foliage sprays, aspen stumps were treated on several acres in an effort to prevent or minimize the development of root suckers. Esteron 245 and Esteron Brush Killer were used in concentrations of one pint and one and one-half pints, respectively, to three gallons of diesel oil. Both the tops and the sides of the stumps were sprayed thoroughly. Two minor variations were introduced on small sections; on one the tops of stumps only were sprayed and on the other water was substituted for oil as a carrier. Foliage Sprays RESULTS If either no effect or complete mortality were found in all cases, udging the results of foliage sprays would offer no difficulty. However, partial damage is often caused and a standard must be adopted in such instances. Assessment of results at Petawawa was based on the following classification. Class A -unharmed Class B- slight damage; growth not retarded to any extent Class C-moderate to severe damage; definitely harmful effects Class D-dead After periodic observations over a two-year period, it was found that all four chemicals were equally effective in killing hazel (Table I). Complete mortality was obtained with each concentration, although it was noted that the lowest, 1,000 p.p.m. acted more slowly than the others.. On the white pine reproduction growing with the hazel, no difference could be discerned between the action of the four chemicals. Concentrations of 1,000 p.p.m. caused little or no damage, but not consistently so, while 5,000 p.p.m. proved definitely harmful in most cases. These concentrations refer to the acid content in the herbicide as related to volume of carrier. Tables are readily available showing the amount of carrier to use with different herbicides to obtain specific concentrations. 5

8 In the separate experiment where individual softwoods were sprayed with 1,000 and 3,000 p.p.m. concentrations, no harm was caused by any of the chemicals used. The white pine, red pine and white spruce involved were in the open and were large and more vigorous than the white pine growing with the hazel. This might account for their better resistance against the 3,000 p.p.m. concentration. The aspen root suckers reacted much the same-as hazel, that is, all concentrations of 1,000 p.p.m. and above proved effective with any of the four chemicals. Red maple was damaged severely by any combination of the chemicals and concentrations tested, but in practically all cases new shoots appeared at the base of the stem shortly after treatment. Only very temporary control was therefore achieved. Stump Sprays None of the treatments of aspen stumps were successful. New root suckers appeared and excavations showed that they sprouted from roots originating from the treated stumps. The lack of success may have been caused by delay between cutting and treatment. The aspen was cut in late winter and the stumps treated in the early spring. DISCUSSION AND CONCLUSIONS From the foregoing results, it appears that a foliage spray at a concentration of 2,000 p.p.m. could be used to release white pine and other conifers from hazel underbrush and aspen root suckers. In the experiments described, practically no damage was caused to the softwood reproduction at this concentration, although it was sprayed as thoroughly as the competing hazel and aspen. Insofar as choice of chemicals is concerned, the results showed no difference in action between 2, 4-D, 2,4, 5-T, and a combination of the two. As the 2, 4-D is much less expensive, this would be the logical herbicide to use. In practice, about one-half gallon of 2, 4-D ester would be required in 100 gallons of water. The above results do not agree entirely with the table of susceptibility provided by Rudolf (5), in which only fair control of hazel is listed for concentrations of 1,000 to 4,000 p.p.m. His table, however, was derived from a number of other publications, some of which were conflicting. The findings of other investigators such as Day (2) corroborate the results at Petawawa, a concentration of around 2,000 p.p.m. being recommended for susceptible species such as hazel or aspen. Sprouting was observed on practically all the hazel at Petawawa two years after treatment. It was not large or dense enough at this time to offer competition to the pine reproduction. It is likely that the pine would have a fiveyear period during which growth would not be suppressed because of hazel competition. On the problem of new hazel growth appearing, Zehngraff and von Bargen (7) found that spraying before July resulted in more sprouting, a point which is worth bearing in mind. Further work should be done on the treatment of aspen stumps to prevent root suckering. Ammate (ammonium sulphamate) has been used with some success but this chemical is quite expensive. U sing herbicides such as 2, 4, 5-T is also costly because of the high concentration necessary. Therefore, at the present time foliage spraying of aspen suckers might prove to be the most economical method of eradication. From an experimental point of view, information is lacking on the time permissible between cutting of aspen and effective treatment of the stumps with herbicides or ammate. Studies have been initiated at Petawawa on this problem. 6

9 SUMMARY One of the silvicultural problem$ at the Petawawa Forest Experiment Station, Chalk River, Ontario, is to achieve complete or substantial eradication of hazel underbrush and aspen root suckers to release white pine reproduction. Unless so freed, this reproduction will remain in a suppressed condition for several decades. A study was therefore made of the effect of different herbicides, in several concentrations, on both vegetation and pine;) reproduction. \, Four herbicides were tested as foliage sprays-dow Formula 40, Esteron 44, Esteron 245, and Esteron Brush Killer. Concentrations used were 1,000, 3,000, and 5,000 p.p.m. (parts per million). Milacre quadrats containing hazel, aspen, and pine were sprayed until all foliage reached the "dripping point". As a supplementary test, individual white pine, red pine, and white spruce were subected to similar treatment, omitting the highest concentration and one herbicide. From the results, it was concluded that the herbicides tested were equally effective. Further, concentrations of 1,000 and 3,000 p.p.m. were toxic to the hazel and aspen but caused little or no damage to the pine reproduction. The highest concentration, 5,000 p.p.m., caused variable damage to the pine. Aspen stumps were treated with high concentrations of Esteron 245 and Esteton Brush Killer in diesel oil to prevent root suckering. The treatments were unsuccessful, possibly because of a time lapse between cutting and treatment. Further studies are planned to gain additional information on the use of stump sprays. TABLE I FOLIAGE SPRAYS-RESULTS 2 YEARS AFTER TREATMENT A-unharmed. B-slight damage. C-severe damage. D-complete mortality. *sprouting evident (NOTE;-Results shown are for two milacre quadrats per concentration.) Species Concentration CHEMICAL Formula 40 Esteron 44 Esteron 245 Esteron Brush Killer hazel 1000 p.p.m. D,D* D D* D* D* D*, D* 3000 " D D" D. D* D,'D D" D* 5000 " D;D D,'D" D*, D* D,'D" w. pine r. pine aspen r. maple " A,A A,A A,A A,A " A,C A,B A,A C,C " C,C C,C A,A A,C " D D D D " D D D D " D D D D " D" C* D* C " C C' D* D* " C' C* D* D* 7

10 REFERENCES (1) AHLGREEN, G. H., G. C. KLINGMAN and D. E. WOLF Principles of weed control. John Wiley and Sons, N.Y. (2) DAY, M. W How to control undesirable trees 'and shrubs. Michigan Agricultural Experiment Station. Quarterly Bulletin, V (3) HALLIDAY, W. E. D A forest classification for Canada. Canada, Dept. Mines and Resources. Lands, Parks and Forests Branch. Forest Service Bulletin 89. (4) ONTARIO DEPARTMENT OF AGRICULTURE Chemical weed control. Extension Circular No. 75. (5) RUDOLF, P. O Chemical control of brush and tree growth for the Lake States. United States Dept. of Agriculture, Misc. Report No. 15. Lakes States Forest Experiment Station. (6) SUGGITT, J. W The chemical control of right-of-way growth; the foliage spraying of resistant woody plant growth; basal bark dormant season treatments on resistant plant species. Papers presented at the Northeastern Weed Control Conference, New York City. (7) ZEHNGRAFF, P. and J. VON BARGEN Chemical brush control in forest management. J. For. Vol. 47, No.2. TECHNICAL NOTES Published by the Forest Research Division 1955 No. 1 No. 2 Strip-cutting in a Mixed Pine Stand J. W. Fraser and J. L. Farrar Seeding and Planting of Spruce on Cut-over Lands of the Subalpine Region of Alberta A. W. Blyth No. 3 Factors Influencing White Spruce Reproduction in Manitoba and Saskatchewan J. S. Rowe No. 4 No. 5 No. 6 No. 7 No. 8 No. 9 An Observation of Weevil Damage in Norway Spruce... M. J. Holst Thinning in a White Pine Stand B. C. Wile Development of a Balsam Fir and White Spruce Forest in Northwestern New Brunswick A. B. Vincent A Summary of the Management Plan for the Green River Area, New Brunswick D. E. Nickerson and A. B. Vincent A Forest Survey Method H. E. Seely Standard Volume Tables for Lodgepole Pine in Alberta.... A. W. Blyth No. 10 Survival of White Spruce Re{lroduction Resulting from Various Methods of Forest SOlI Scarification..., D. 1. Crossley No. 11 Yield of White Spruce and Balsam Fir in an Undisturbed Stand, Duck Mountain, Manitoba... R. T. Pike No. 12 No. 13 Slip-on Tankers for Forest Fire Suppression... '" An Integrating Light Meter for Ecological Research... '" J. S. MacTavish K. T. Logan No. 14 A Method of Determining Approximate Merchantable Volumes G. H. D. Bedell and A. B. Berry 8

11 1955-Continued No. 15 No. 16 No. 17 No. 18 No. 19 No. 20 No. 21 No. 22 Effect of Watering, Shading, Seed-bed Medium, and Depth of Sowing on Red Pine Germination J. W. Fraser and J. L. Farrar Early Developments in a Subalpine Lodgepole Pine Stand of Fire Origin K. W. Horton Average Height Weighted By Volume in Air Photo Interpretation... F. D. MacAndrew8 Yield of Even-aged Fully Stocked Spruce-Poplar Stands in Northern Alberta... W. K. MacLeod and A. W. Blyth Lodgepole Pine Studies at the Strachan Experimental Block in Alberta...'... D. I. Crossley Northern Clay Belt Growth and Yield Survey... D. W. MacLean and G. H. D. Bedell The Petawawa Plantations... W. M. Stiell Fire Hazard Resulting from Jack Pine Slash...,...,.. D. E. Williams No. 23 No. 24 The Effect of Various Slash Disposal Methods on the Regeneration of Cut-over Jack Pine Stands Mechanical Scarification to Induce White Spruce Regeneration in Old Cut-over Spruce Stands H. J. Johnson D. 1. Crossley No. 25 The Production and Dispersal of Lodgepole Pine Seed... D. 1. Crossley 1956 No. 26 No. 27 No. 28 No. 29 No. 30 No. 31 No. 32 No. 33 No. 34 No. 35 No. 36 Forestry Problems of the Bonavista Peninsula, Newfoundland W. C. Wilton and H. S. Lewis Site Types, Growth and Yield, Lake Edward, Laviolette County, Quebec... R. G. Ray Planting of Conifers in the Spruce Woods Forest Reserve, Manitoba, J. S. Jameson Scion Storage and Graft Protection in the Spring Grafting of Red Pine M. J. Holst Assessment of Site Productivity in Dense Lodgepole Pine Stands... " L. A. Smithers Plantations of the Acadia Forest Experiment Station... J. W. McLeod The Possibility of Continuous Planting of White Spruce Throughout the Frost-free Period...,... D.1. Crossley Greenhouse Grafting of Spruce and Hard Pine at the Petawawa Forest Experiment Station, Chalk River, M. J. Holst, Ontario J. A. Santon, and C. W. Yeatman Mechanical Scarification and Strip Clearcutting to Induce Lodgepole Pine Regeneration... D. 1. Crossley Fruiting Habits of Lodgepole Pine..., D.!. Crossley The Effect of Certain Vegetation Eradicators on the Inflammability of Various Materials..., E. J. Ward 9

12 EDMOND CLOUTIER, C.M.G., O.A., D.S.P. QUEEN'S PRINTER AND CONTROLLER OF STATIONERY OTTAWA, 1956