PROGRAM TITLE: Disturbance Ecology (DISTURB) ACTIVITY STREAM: Process/Observation/Modeling/Assessment SCIENCE ELEMENT:Ecological System/Biogeochemical Dynamics U.S. DEPARTMENT OF AGRICULTURE Forest Service Global Change Research Program (FSGCRP) DESCRIPTION: The Forest Service Program includes the world's pre- eminent efforts to understand and predict the occurrence and ecology of natural disturbance agents; including fire, insects and disease, and storms. Continuing research is improving the understanding of disturbance climatology, disturbance ecology, and biogeochemistry. On the regional to global scales, natural disturbances substantially affect the rate of ecosystem conversion and the rate of carbon emissions to the atmosphere; so the management of disturbance is a high-priority policy area for mitigation and adaptation strategies. Predicting disturbance frequency is required to predict changes in ecosystem distribution because all ecosystems are adapted to a more-or-less specific disturbance regime. The rate of change in ecosystems and their distribution is also controlled by the disturbance regimes; so the transient response of ecosystems cannot be predicted without predicting the effect of disturbance. Anticipating natural disasters and changes in the atmosphere-biosphere carbon balance also require improved consideration of disturbance processes. In FY 1995 we will accelerate research to analyze changes in fuel buildup and fire hazard due to global change and to predict wildland fire activity and emissions with global change. The forest health monitoring program will be expanded, and additional modeling of forest pest interactions with climate will be undertaken. We will develop methods to model all types of disturbance changes based on Global Circulation Model outputs. STAKEHOLDERS: Important partnerships have been formed to investigate natural disturbances with EPA, NSF, NASA, DOI, and DOE Global Change Programs. International Agreements and partnership with US AID have created very significant Programs in Brazil, Mexico, and Russia. Beneficiaries include the agencies that manage disturbance and protect resources and society from their impact, and the community of scientists and policymakers concerned with natural and human-induced changes in the global Earth system. SHORT-TERM POLICY PAYOFFS: Policymakers will benefit from an assessment of the magnitude of increases in disturbance frequency and severity, and from the initial attempts to predict transient ecosystem response to climate change that will be available in 2-3 years. Improved estimates of global atmospheric emissions from forest fires and from ecosystem conversion will also be available in that timeframe.