Various management schemes involving herbicides have been successfully used to achieve ROW management goals during the first maintenance cycle following an initial clearing phase of electric utility ROW vegetation management. Two herbicide mixtures were used to determine which application mode (selective or nonselective) and method (basal or stem-foliar) is most cost effective in accomplishing vegetation management objectives during the second phase of ROW vegetation management — first-maintenance cycle. This study is a follow-up to an initial clearing research study (1).
Materials and Methods
Study area description.
Studies took place on Niagara Mohawk Power Corporation’s Volney-Marcy 345 kV transmission right-of-way in Oneida County, New York. The study area has been described in detail in the previous study on initial clearing of this ROW (1).
Experimental design and treatments.
randomized complete block design was used to test maintenance (four treatments, three replications, two blocks) treatment effects on ROW vegetation. Treatments were applied on initial clearing study plots which ranged in size from 0.4 to 2.1 ac (1). Treatments were blocked across a contiguous 15 mile section of ROW between abandoned agricultural land and woodland areas. A prestudy inventory of vegetation was conducted in 1982. The ROW was cleared and treated in spring 1983 using selective and nonselective mechanical and herbicide application modes (1). A post treatment evaluation was conducted in fall of 1983, followed in the summer of 1984 by the First Maintenance Cycle treatments. A post treatment vegetation survey was completed in the fall of 1987 to evaluate the first maintenance cycle treatments.
The four study treatments were composed of two basal and two stem-foliar herbicide treatments applied selectively and nonselectively:
Selective basal.
Basal treatment of selected undesirable woody vegetation with a herbicide formulation consisting of 2 gal of triclopyr at 4.0 lb active ingredient (a.i.)/gal (3,5,6-trichloro-2-pyridyI-oxyacetic acid) (Garlon™ 4) and 98 gal oil; it was targeted at the lower 1 to 2 ft of individual stems, saturating the base of the stem and all exposed roots to the point of rundown and puddling around the root collar zone.
Nonselective basal.
Basal Treatment of nonselected woody vegetation with a herbicide formulation consisting of 2 gal of triclopyr at 4.0 lb a.i./gal and 98 gal oil; it was targeted at the lower 1 to 2 ft of individual stems as in selective basal. Selective stem-foliar. Stem-foliar treatment of selected woody vegetation with a herbicide formulation consisting of a mixture of 1.5 qt of triclopyr at 4 lb a.i./gal, 2 qts of a formulation of picloram at 0.5 lb a.i./gal plus 2,4-D at 2 lb a.i./gal (4,Amino-3,5,6-trichloropicolinic acid and 2,4-Dichlorophenoxyaceticacid) (Amdon™ 101), 1 qt of surfactant (Surfel™) and 99 gal water, applied to leaves, branches and stems to a point of wetness.
Nonselective stem-foliar.
Stem-foliar treatment of all woody vegetation with a herbicide formulation consisting of a mixture of 1.5 qt of triclopyr at 4 lb a.i./gal, 2 qts of a formulation of picloram at 0.5 lb a.i./gal plus 2,4-D at 2 lb a.i./gal, 1 qt of surfactant and 99 gal water, applied to leaves, branches and stems to a point of wetness as in selective stem-foliar.
Data collection and analysis.
Treatment costs were based on current year (1984) contractor billing rates for labor, equipment and herbicide mix for our small study plots. Although the actual costs per treatment may be higher than if done on larger operational plots, the cost ratios between treatments would not change.
Plant community development was periodically monitored since 1983 by surveying total species density (sprout or seedling) and number of stems > 6 ft height on systematically located strip transects covering 7% of the treatment plot area. Plants were classified as undesirable or desirable. Desirables are any vegetation, including trees and shrubs, that attain maximum heights of < 20 ft. Undesirables are any vegetation, mainly trees, that attain maxium heights > 20 ft. Percent herbaceous cover was tallied separately using point samples (4 ft2 quadrats) located at 10 ft intervals down the center of each strip transect.
Analysis of variance and covariance were used to test treatment effects on undesirable and desirable plant density, percent of undesirable stumps that sprouted, number of stems > 6 ft height, herbaceous cover and treatment costs. Means were separated using Duncan’s Multiple Range Test.
Interpretation of cost effectiveness for the first maintenance cycle treatments was based on both vegetation control (1983 vegetation pre treatment survey vs. 1987 vegetation post treatment survey) and treatment cost (1984). A treatment that would decrease undesirables, increase desirables and maintain relatively low costs was determined as most cost effective.
Results
First Cycle Maintenance.
There were no differences between desirable and undesirable stems among selective and nonselective basal and stem-foliar treatments 1-year pre- (1983) and 3 years posttreatment (1987) (Table 1). The number of stems > 6 ft height 3 years post treatment was not different among treatments (Table 1). Total herbaceous cover did not differ among treatments 3 years posttreatment, all plots had over 100% cover (Table 1). Treatment costs were different among treatments; basal costs were nearly twice that of stem-foliar (Table 1).
Conclusion
Given equal reduction of undesirables and promotion of desirables, cost effectiveness of the first maintenance cycle can be based on treatment costs alone. Basal treatment cost was nearly double that of stem-foliar; therefore, stem-foliar treatments using either a selective or nonselective mode is most cost effective.
Optimum Stocking of Urban Trees.
Norman A. Richards, SUNY College of Environmental Science and Forestry, Syracuse, NY.
Promotions of urban tree planting tend to ignore the broader tree management concept that optimum stocking usually is not the maximum possible, but rather, depend on site-specific benefits and costs of trees in relation to the greenspace resources that can support their growth. Based primarily on observations in Syracuse, NY, this paper offers concepts for wider testing as to adaptation of forestry concepts of stocking to three general categories of urban tree conditions: 1) urban woods, where forest stocking concepts are directly applicable, 2) urban savanna and street tree strips, the largest area component in most communities, with substantial greenspace interspersed with structures. Here, optimum stocking commonly is held below the biological potential of the greenspace by non-tree values, and depends on many site-specific factors, and 3) trees in paving, mostly in central-city areas, where optimum stocking depends on the potential and willingness to create adequate quality spaces to support trees.
The Influence of Soil pH on the Activity of Paclobutrazol, Flurprimidol and Uniconazole.
D.E. Wachter, H.A.Holt and W.R. Chaney, Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907.
This study was conducted to determine whether soil pH has a significant effect on the uptake of three tree growth regulators (TGRs) by seedlings of silver maple (Acersaccharinum) and American sycamore (Plantanus occidentalis). A Hanna series loam, with a pH of 5.0, was treated to raise the pH to 6.5 and 8.0. Two concentrations (1X and 10X) of three TGRs (paclobutrazol, flurprimidol, and uniconazole) were incorporated into the soil after dissolving the technical grade of the active ingredient in isopropyl alcohol. One-year-old American sycamore and silver maple seedlings were planted into soil containing the pH-TGR treatment combinations. Soil drenching treatments, using the same concentrations, soil pHs, TGRs and tree species were also established. A randomized complete block design with six replications per treatment were established for both experiments. The height of the dominant stem at 90 days after treatment was recorded. The data were analyzed using a 4-way analysis of variance followed by a comparison of means. American sycamore showed a significant difference in the 4-way interaction of pH-application method-regulator-concentration. Silver maple did not show a significant difference in the 4-way interaction. Comparing the treatment of pHs to each other, pH 5.0 was regulated the most followed by 6.5 and 8.0. The drench application demonstrated the most regulation, especially with the flurprimidol treatments at the 10X concentration.
- © 1991, International Society of Arboriculture. All rights reserved.
Literature Cited
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