Forty-one years of population change and community succession in aspen forests on four soil types, northern lower Michigan, USA.

In 1938, 4 permanent 0.04-ha plots were established in pioneer aspen (Populus grandidentata, P. tremuloides) forest on dry-mesic to wet-mesic soils. Five patterns of change in species populations are identified, reflecting differences in reproductive characteristics and physiological requirements of the species: 1) early dominance, 2) delayed dominance, 3) persistence, 4) progressive recruitment, and 5) late recruitment. Patterns 1, 3 and 4 predominated on dry-mesic soils, reflecting slow replacement of aspen by Pinus resinosa and P. strobus from seedling origin. All 5 patterns occurred on the mesic soil where Acer rubrum, A. saccharum and Fagus grandifolia increased in importance through both vegetative sprouting and seedling establishment. Recruitment on the dry-mesic soils did not correspond to the stages of development of the aspen overstory as determined from -3/2 thinning curves. In contrast, recruitment and growth in the understory appeared to be dependent upon the occurrence of canopy openings on the mesic soil. Species populations responded to insect defoliation on the wet-mesic plot.-from Authors

Duke Scholars

Author Curtis J. Richardson Environmental Sciences and Policy