Abstract
Witness trees provide information fundamental for restoration ecology, often serving as baselines for forest composition and structure. Furthermore, when categorized by fire relations, witness trees can shed light on past disturbance regimes. Kriging was applied to witness-tree point data to form a contiguous surface of pyrophilic percentage for four national forests in the northeastern United States. Fire was found to be an important disturbance agent on the Allegheny and Finger Lakes National Forests, often corresponding to large river systems and lakesides where Native American activities were concentrated. In contrast, fire was relatively unimportant on the Green Mountain and White Mountain National Forests based on the witness-tree record. There, the cool, moist year-round climate, coupled with lower Native American population densities, greatly subdued fire, supporting the local view of these as "asbestos" forests. When applying this method to town-level witness-tree data for the entire northeastern United States, we found a distinct east-west line dividing areas of high (south) and low (north) pyrophilic percentage. Known as the tension zone line, the undulating character of this boundary, penetrating northward along major river valleys, underscores the importance of Native Americans as a disturbance agent on the presettlement landscape.
Keywords
fire,
presettlement disturbance regimes,
Native Americans
Citation
Thomas-Van Gundy, Melissa A.; Nowacki, Gregory J.; Cogbill, Charles V. 2015. Mapping pyrophilic percentages across the northeastern United States using witness trees, with focus on four national forests. Gen. Tech. Rep. NRS-145. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 26 p.
