Global Change and Forest Soils

While global-change impacts can affect soils directly and indirectly, the largest impacts on forest-soil carbon over decades to centuries are from changes in land use and vegetation cover. Climate change is expected to affect temperature-sensitive biogeochemical processes, including litter decomposition, soil respiration, N mineralization, nitrification and denitrification, trace gas emissions, as well as root dynamics and plant productivity. The relationship between soil temperature and Carbon-di-oxide flux can account for a large proportion of the seasonal variation in soil respiration, but temperature alone is not the only factor that can control soil decomposition and N mineralization. Forests are typically limited by nitrogen, especially in coniferous forests. Species composition and successional changes under global-change conditions may alter the vegetation cover and affect soil carbon storage. J. P. Caspersen et al. compared biomass/age relationships with historical biomass/age relationships using forest inventory data and a statistical approach.