Vegetation Dynamics on a Managed New York Right-of-Way (1977–1996)

Lawrence W. Jackson

Vegetation surveys were conducted on an upgraded electric transmission right-of-way in eastern New York with an initial ocular estimate of ground cover at the time of clearing (1977) and subsequent ocular surveys of 12 representative sites in 1983, 1991 and 1996. Objectives were to document treatment effectiveness and vegetation change over time. Plants were classified as mosses, ferns, grasses and sedges, forbs, shrubs, desirable trees and undesirable trees. Treatments of vegetation occurred in 1978 (basal with 2, 4, 5-T), 1983 (cut/stump with picloram), 1991 (cut/stump, foliar with glyphosate and imazapyr) and 1996 (spot foliar with glyphosate). Over the study period ground cover of mosses, ferns and grasses/sedges declined while forbs, shrubs and desirable trees increased. Undesirable trees were reduced to 5% or less ground cover on 10 sites with only one site increasing and one remaining stable. The basal treatment in 1978 eliminated many non-root sprouting species, but it took a follow-up cut/stump application in 1983 to remove root sprouting species. Subsequent treatments reduced undesirable species to 5% or less ground cover by 1996 on all but one site. Thus, major conversion to forbs, shrubs, and desirable tree species began in the second treatment cycle. Species numbers increased over the years in all but the moss group, with a regression analysis of variance yielding an f value of 438.97, df 1 (highly significant at the 0.05 level). While undesirable trees are now 5% or less of ground cover they continue to invade and will require continuous cyclical maintenance to preclude their escape into the wire security zone.

Keywords: Vegetation dynamics, vegetation survey, ocular estimate, selective treatments, ground cover, conversion, biodiversity