© 1986 Heron Publishing—Victoria, Canada
A comparison of rates of aboveground growth and carbon dioxide assimilation by aspen on sites of high and low quality
G. M. Briggs (1, 2), T. W. Jurik (1, 3) and D. M. Gates (1)
1. University of Michigan Biological Station, Pellston, Michigan 49769, USA / 2. Biology Department, SUNY-Geneseo, Geneseo, NY 14454, USA / 3. Iowa State University, Ames, Iowa 50011, USA /
Summary
Net assimilation rates of 10-year-old naturally regenerated bigtooth aspen (Populus grandidentata Michx.) at two sites in northern Michigan, USA, were compared to test the hypothesis that site-related differences in aboveground
production depends solely on differences in rates of CO2 assimilation. On a leaf weight basis, aboveground production on the better site was over twice that on the poorer site, whereas
maximum CO2 assimilation rates on the better site were only 48% higher, leading to a rejection of the hypothesis. Soil respiration rates
on the two sites were comparable, suggesting that the difference between sites in aboveground production can be attributed
in part to a difference in the proportion of total assimilate allocated belowground.
