Kinetics of microbial respiration and nitrogen mineralization in Great Lakes forests

Rates were measured at which C and N were released from labile organic matter within the forest floor and mineral soil of jack pine, red pine, balsam fir, sugar maple, and quaking aspen forests. Samples were assayed using a long-term laboratory incubation and pools and rate constants were compared among forests. Labile (respired) C pools in forest floor ranged from four to six times less than that measured in mineral soil. Annual in situ estimates of microbial respiration and N mineralization were far less than respired C and mineralized N pools, suggesting that only a fraction of labile soil organic matter is annually metabolized within these forests. Local climate appears to be an important factor. -from Authors