PREDICTING THE EFFECT OF FIRE ON LARGE-SCALE VEGETATION PATTERNS IN NORTH-AMERICA - ABSTRACT

Changes in fire regimes are expected across North America in response to anticipated global climatic changes. Potential changes in large-sca le vegetation patterns are predicted as a result of altered fire frequ encies. A new vegetation classification was developed by condensing Ku chler potential natural vegetation types into aggregated types that ar e relatively homogeneous with respect to fire regime. Transition rules were developed to predict potential changes from one vegetation type to another because of increased fire frequency. In general, vegetation currently associated with warmer or drier climates could replace exis ting vegetation in most biomes. Exceptions are subalpine forests and w oodlands at the Arctic treeline, which are predicted to become treeles s. The transition rules provide an ecological perspective on possible new configurations of vegetation types, a set of constraints for stead y-state models, and a potential method of calibration for dynamic mode ls of large-scale vegetation change.