MOTOR-MANUAL, MECHANICAL, AND HERBICIDE RELEASE AFFECT EARLY SUCCESSIONAL VEGETATION IN NORTHWESTERN ONTARIO

Cover and height of vegetation before and one growing season after: 1) motor-manual cutting, 2) mechanical brush cutting (Silvana Selective/ Ford Versatile), 3) aerial application of Release(R) (a.i. triclopyr) herbicide, 4) aerial application of Vision(R) (a.i. glyphosate) herbic ide, and 5) control (no treatment) were quantified. Multivariate analy sis permitted the study of vegetation response as a whole, while accou nting for correlations that exist among the individual vegetation grou ps. Univariate analysis were used to study the responses of individual vegetation groups. Although no pretreatment differences in percent co ver were observed (P = 0.128), deciduous tree, shrub, forb, grass, and sedge groups responded differently to the treatments after one growin g season (P < 0.018). Post-treatment cover of deciduous tree and shrub groups was lower in herbicide treated plots than in cut plots. Forb, grass and sedge covers varied greatly among treatments. Brush saw and Silvana Selective treatments decreased cover of deciduous trees. Relea se(R) decreased cover of deciduous trees and shrubs. Vision(R) decreas ed cover of deciduous trees, shrubs and ferns. Cover of all vegetation groups increased on the untreated control. Among the conifer release treatments examined, Vision(R) reduced woody and herbaceous vegetation most.