You are here: Home / Research Topics / Research Highlights / Individual Highlight

Research Highlights

Individual Highlight

“Witness Trees” as Indicators of Past Fire

Photo of A map showing the boundaries of Pennsylvania, New Jersey, New York, Massachusetts, Connecticut, Rhode Island, Vermont, New Hampshire, and Maine.  The outlines of four national forests are also included.  The results of calculating the percentage of pyrophilic witness tree species from town-level surveys are displayed as a color gradient from red to green, with red indicating a high percentage of pyrophilic species and green a low percentage.  The red starts in the south and grades to green further north.  Also displayed is an approximation of the tension zone line between generally wetter forests to the north and drier forests to the south. USDA Forest ServiceA map showing the boundaries of Pennsylvania, New Jersey, New York, Massachusetts, Connecticut, Rhode Island, Vermont, New Hampshire, and Maine. The outlines of four national forests are also included. The results of calculating the percentage of pyrophilic witness tree species from town-level surveys are displayed as a color gradient from red to green, with red indicating a high percentage of pyrophilic species and green a low percentage. The red starts in the south and grades to green further north. Also displayed is an approximation of the tension zone line between generally wetter forests to the north and drier forests to the south. USDA Forest ServiceSnapshot : In ecosystem restoration, the question of “What was it like back then?” is often difficult to answer. Understanding and mapping forest composition from before European settlement is an important basis for ecosystem restoration, helping to ensure the return of fire into ecosystems that formerly burned. Forest Service scientists used “witness trees,” which are trees indicated on old maps and land surveys, to help identify trees that grew in the past.

Principal Investigators(s) :
Thomas-Van Gundy, Melissa 
Research Location : Monongahela National Forest, West Virginia; New England
Research Station : Northern Research Station (NRS)
Year : 2015
Highlight ID : 875

Summary

The recognition that disturbance played a key role in determining past vegetation compositions, structures, and patterns has spurred efforts to map fire regimes for ecosystem restoration. The need for higher resolution maps for land management has led to an increasingly sophisticated array of maps combining soils, topography, human history, remnant vegetation, landscape concepts, and local knowledge. Forest Service scientists classified tree species by fire relations (pyrophilic, or fire loving; and pyrophobic, or not fire loving) and applied the classification to witness trees listed in deeds and other forms of early land surveys. From this classification, the scientists calculated a pyrophilic percentage spatially extrapolated these percentages to form a continuous surface across large landscapes. This technique was applied to witness trees on the Monongahela National Forest in West Virginia, resulting in a set of maps that can be used by the forest to help in returning fire as a disturbance regime. Similar maps were created for the Allegheny, Finger Lakes, Green Mountain, and White Mountain national forests and, at a different scale, for the New England region. These spatial models can be used by fire planners and ecologists as aides to determining where to return fire on the landscape or site scale.

Forest Service Partners

External Partners

  • Greg Nowacki, USDA-Forest Service, Eastern Region, Regional Ecologist
  • Charles Cogbill, Harvard University, Ecologist
  • Jason Teets, USDA-Natural Resources Conservation Service, Ecological Site Description Specialist

Strategic
Program Areas

Priority
Areas