Correlation of Leaf Area Index to Root Biomass in Populus tremuloides Michx supports the Pipe Model Theory

There is relatively little information about the root systems of mature trees. Ecophysiological theory predicts that the size and extent of mature root systems would be correlated with leaf area and aboveground biomass within groups such as species or populations. Using recent methods for root sampling that reduce bias and improve representativeness, we tested these hypotheses for quaking aspen (Populus tremuloides Michx.) in California. We found that for a representative sample of basal areas for this species, the leaf area index (LAI) was a highly significant predictor of both coarse and fine root biomass (adj. r2 of .79 and .59, respectively). Coarse root biomass was a highly significant predictor of fine root biomass (adj.r2 of .84). Results support the pipe model theory, and may prove useful for land managers interested in root systems for aspen stand regeneration or management for carbon sequestration.