EFFECT OF DISTANCE FROM FOREST EDGE ON REGENERATION OF RED SPRUCE ANDBALSAM FIR IN CLEARCUTS

We quantified regeneration of red spruce (Picea rubens Sarg.) and bals am fir (Abies balsamea (L.) Mill.) in regrowing montane and lowland fo rest clearcuts at different distances from the intact forest edge to d etermine the extent to which disturbance size affects stem densities a nd distributions. Regeneration of fir in clearcuts (0.8-5.3 stems/m(2) ) was only 6-20% of regeneration occurring in corresponding, intact fo rests. Lowest densities generally occurred at the farthest distances f rom forest edge (50-100 m) where seed densities were lowest. Regenerat ion of spruce, in contrast, was similar in clearcuts and intact forest s (0.07-1.4 stems/m(2)), due in large part to greater seed dispersal. Density of regenerating spruce was much lower than fir throughout (usu ally < 20% of fir), but species differences were most extreme in intac t forests (where fir regeneration was 5-53 times higher than spruce) a nd least extreme in clearcuts at distances farthest from the forest ed ge (where regeneration of fn was only 1.1-3.4 times higher than spruce ). Near the forest edge (5 m in the forest to 5 m into the clearcut), regenerating spruce and fir were positively associated with preexistin g overstory trees of the same species.