A Conceptual Framework for Fire Ecology in a Changing Climate
Abstract
Climate interacts with forest dynamics and wildfire at a range of spatial and temporal scales. The purpose of this talk is to describe (and ideally discuss) an emerging conceptual model that describes how scale dependent patterns of climatic variability (a top-down control) interact with processes of vegetation development and topography (bottom-up controls) to give rise to characteristic disturbance regimes and observed patterns of wildfire throughout North America. At the shortest timescales (synoptic to seasonal), climate influences fine fuel moisture, ignition frequency, and rates of wildfire spread. At intermediate timescales (annual to interannual), climate affects the relative abundance and continuity of fine fuels, as well as the abundance and moisture content of coarser fuels. At longer timescales (decadal to centennial) climate determines the assemblage of species that can survive at a particular location. Interactions between these species’ characteristics and the influence of climatic processes on wildfire activity give rise to the characteristic disturbance regime and vegetation structure at a given location. Large-scale modes of climatic variability such as the El Niño - Southern Oscillation and the Pacific Decadal Oscillation affect patterns in wildfire by influencing the relative frequencies of shorter scale processes. Because the importance of these processes varies depending on topographic position and the ecology of the dominant vegetation the effects of these modes varies both within and between regions. Global climatic change is effectively a centennial to millennial scale process, and so its effects can be understood as resulting from interactions between the observed patterns of higher frequency processes, as well as processes of vegetation change whose temporal evolution exceeds the length of the observational record. Statistical models of future fire that are based on historical fire climate relations and regionally downscaled climate forecasts suggest that in most regions of North America wildfire will increase in frequency over the next several decades. Predictions beyond this interval are probably unreliable as vegetation structure and composition will be changing rapidly in response to changing climatic conditions and fire regimes. I plan to end this talk with a longer than typical opportunity for discussion of the implications for fire ecology and climatic change research.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMNH34A..01G
- Keywords:
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- 0439 BIOGEOSCIENCES / Ecosystems;
- structure and dynamics;
- 0468 BIOGEOSCIENCES / Natural hazards;
- 1630 GLOBAL CHANGE / Impacts of global change