Interference Factors Responsible for Resistance of Forb-Grass Cover Types to Tree Invasion on an Electric Utility Right-of-Way
W.C. Bramble, W.R. Byrnes, R.J. Hutnik, and S.A. Liscinsky
Abstract: An investigation of factors responsible for resistance of forb-grass cover types to tree invasion was carried out from 1992 through 1994 on an electric transmission right-of-way (ROW) in central Pennsylvania. Unprotected seedspots and seedspots protected by wire cages were installed on the ROW to investigate the effect of the important interference factors of wildlife depredation, plant competition, and allelopathy. This field study was supplemented by pot culture tests of the effect of plant competition, seedbed condition, and allelopathy on tree seed germination and seedling growth in an environment where wildlife depredation, soil moisture, frost damage, and insect and disease attacks were controlled. The major factors that interfered with tree seed germination and seedling growth were wildlife depredation and plant competition by the dominant plant species of the forbgrass cover type, namely, poverty grass (Danthonia spicata), rough goldenrod (Solidago rugosa), and hayscented fern (Dennstaedtia punctilobula).