Competition effects in juvenile jack pine and aspen as influenced by density and species ratios

(1) Jack pine (Pinus banksiana Lamb.) and trembling aspen (Populus tremuloides Michx.) seedlings were grown in replacement series (100, 75:25, 50: 50, 25:75, 100) at variable densities (17 to 10 000 plants m2) for 12 weeks in a greenhouse experiment and for 3 years in a field test. (2) Analyses of survival, height, weight, form, resource allocation, relative yields and relative crowding coefficients indicated that aspen dominated in all mixtures and densities except 10 000 plants m-2.