|Leaf litter produced by aspen and birch (aspen-birch ring
section only) growing under elevated CO2 and O3. Dead fine root biomass
was determined from cores collected in the aspen and aspen-birch ring
sections (Data from Lindroth and Zak, unpublished).
||Rates of soil respiration averaged over the 1999 fiend
season (A), and rates of microbial respiration determined by laboratory
incubation (B; data from King et al 2001 and Zak, unpublished).