Seedfall in a young-growth Douglas-fir stand: 1950–1978

Donald L. Reukema
1982 Canadian Journal of Forest Research  
A 29-year record of seedfall in thinned and unthinned portions of a Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand, spanning ages 39 through 68, reveals annual seed production from no seeds to about 3 million per hectare. For the nine largest crops, annual seedfall in the best seed-producing thinning treatment included at least 100 000 filled seed per hectare. The first of these nine crops was in 1950; the other eight occurred at 1-to 4-year intervals beginning with 1959. For the nine
more » ... largest crops, the proportion of seeds filled averaged 45%o and ranged from 30 to 54%. Typically, about two-thirds of the seed fell by mid-December; but for two of the three largest crops. time of seed shedding was greatly delayed. Thinning substantially increased the number of seeds produced in some years following thinning but the effect was not lasting. There was little or no effect of thinning on the proportion of seed filled or timing of seed dissemination.
doi:10.1139/x82-037 fatcat:nyyuz3zwpjbgfipnrz22pggwhm