Forests and Global Change

Abstract

Forest ecosystems influence climate through physical, chemical, and biological processes that affect planetary energetics, the hydrologic cycle, and atmospheric composition (Bonan 2008). Physical processes at the intersection of the biosphere and geosphere, commonly referred to as biogeophysics, include momentum transfer and land–atmosphere energy fluxes (absorption and reflection of solar radiation, absorption and emission of longwave radiation, partitioning of net radiation into sensible and latent heat fluxes, and storage of heat in the soil). Hydrologic processes include interception of precipitation, throughfall, stemflow, infiltration, runoff, evapotranspiration, soil water dynamics, and snow melt. Forests additionally influence climate and atmospheric composition through biogeochemical processes including the exchanges of CO 2 , CH 4 , N 2 O, biogenic volatile organic compounds, and aerosols with the atmosphere. Forest ecosystems are now recognized as providing important climate forcing and feedback.