PARENT SESSION
Oral Session #7: Disturbance in Forests: Fire, wind, and other.
Presiding: G. Murray
Monday, August 5. 8:00 AM to 11:30 AM. Cochise Meeting Room, TCC.
Wind and fire dynamics in historical Wisconsin forests: a multiscale assessment.
Schulte, Lisa*,1, Mladenoff, David1, 1 University of Wisconsin-Madison, Madison, WI
ABSTRACT- Despite the well-known importance of disturbance in structuring landscape pattern, the combined effect of multiple disturbance types has rarely been studied. Our goal was to elucidate interactions between wind disturbance, fire disturbance, and the environment within Wisconsin's northern forests. Because the effects of humans are pervasive on the current landscape, we used historical data collected prior to Euro-American settlement (mid-1800s) - the U.S. General Land Office Public Land Survey (PLS) notes. These records contain information on the location and extent of moderate to severe levels of windthrow, and crown fire. Both wind and fire exhibited non-random spatial patterns at several scales, and environmental variables were shown to have a strong influence on this pattern. Broad-scale physiography (climate*landform), soil attributes, vegetation, and interactions between these variables were important in explaining the distributions of both wind and fire disturbance. Climatic trend was additionally significant for fire. Contrary to other locations, topographic variables were not important; aspect and slope were never significant predictors and elevation was only significant in a univariate model. The most powerful predictor for fire disturbance was physiography, while the interaction between physiography and vegetation was most important for wind disturbance. Qualitative descriptions within the PLS data offer support for the hypothesized link between these two disturbance types in mesic forest types, with fire following windthrow. A quantitative relationship could not be established, however, suggesting that the incidence of this interaction was rare. These results suggest a new model for understanding disturbances in subtle landscapes, where regional patterning may have a greater overall influence than more local effects. They also offer a point of reference for evaluating wind and fire disturbance in human-dominated landscapes.
KEY WORDS: disturbance modeling, wind and fire, historical landscapes, Wisconsin