While stocks of fire-derived pyrogenic organic matter (PyOM) or black carbon are significant in forest soils worldwide, fundamental uncertainties remain about its structure, degradation rate and how PyOM additions affect native soil organic matter cycling. Dr. Bird will present results from two long-term field studies and related laboratory experiments that examine the fate of dual-labeled (13C/15N) PyOM applied to temperate forest soils derived from several tree species including Pinus ponderosa, Pinus banksia and Acer rubrum and a range of pyrolysis temperatures (i.e., 0, 200, 300, 450 and 600°C). PyOM structures, PyOM and native soil C mineralization rates, PyOM-C utilization by microbial groups (13C-stable isotope probing) and the effect of PyOM additions on microbial community structure and biomass will be discussed.