Processes Affecting Carbon Storage in the Forest Floor and in Downed Woody Debris
Many forests differ from other types of ecosystems, such as grasslands or rangelands, in that they develop a thick horizon of decaying organic matter, together with highly heterogeneous accumulations of woody debris, on the soil surface. The characteristics of the surface organic horizon (O horizon), or forest floor, depend on temperature and rainfall regimes, litter production rates, litter quality, and soil microbial and animal activities. The O horizon varies among forest types and climates from little more than a thin litter layer to very thick and well developed. One of the most well-studied aspects of litter decomposition is the rate of mass loss from foliar and fine-root litters incubated in the field under a variety of temperature and moisture regimes. Though the potential of forest floors to increase carbon storage are directly related to changes in litter inputs, they are mediated by complex interactions with other aspects of environmental change.