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Individual Highlight

Potential Fire Behavior Depends on Cutting Pattern in a Montana Lodgepole Pine Forest

Photo of Satellite imagery of clumped (lower left) and dispersed retention (upper right) at Tenderfoot Creek Experimental Forest, Montana. U.S. Department of Agriculture Forest ServiceSatellite imagery of clumped (lower left) and dispersed retention (upper right) at Tenderfoot Creek Experimental Forest, Montana. U.S. Department of Agriculture Forest ServiceSnapshot : Forest Service researchers tested silvicultural treatments that can minimize the probability of severe wildfires and create resilient forests. They found that evenly spaced trees blew down easier; seedlings in lodgepole pine forets need to be included in fire behavior calculations because the added to surface fuels; and that cutting and burning treatments in lodgepole pine forests can create complex structure in lodgepole forests and promote resilience to wildfire.

Principal Investigators(s) :
Sutherland, Elaine K. Wright, David K.
Research Station : Rocky Mountain Research Station (RMRS)
Year : 2016
Highlight ID : 946

Summary

Many lodgepole pine forests in Montana were historically a mix of ages and tree sizes as a result of mixed-severity fires. Now the forests have trees mostly the same size and crowns touch so that when fires burn, they burn as large and severe crown fires. These fires can be dangerous and expensive to fight, leading to the loss of human and natural resources. Forest Service researchers are looking at silvicultural treatments that can minimize the probability of severe wildfires and create resilient forests. In 2000, lodgepole pine stands in Montana were cut and prescribed-burned in two patterns: one resulted in evenly spaced trees and the second resulted in clumps of trees separated by clearcut openings. The objective was to evaluate these treatments as ways of restoring forests and managing fire behavior. The questions the researchers asked were: (1) Does the cutting pattern and use of prescribed fire influence fuel dynamics? And, (2) Are there differences in potential fire behavior due to cutting patterns and the burn treatments? In this study they tested how the treatments actually affected potential fire behavior 12 years after treatment. In 2011 they were re-measured. Because fires burn on the ground surface and in the crowns of trees, they calculated the amount of fuel on the surface and in the tree crowns. They then used statistical models to estimate the probabilities that fires would burn and spread on the surface, move (transition) into the crowns, and spread through the forest. The researchers found that more trees were blown down in the evenly spaced treatment compared to the clumped treatment; mortality from the prescribed fires was similar in both cutting patterns; and, the contribution of seedlings to fuel loads is not typically calculated but lodgepole pines grow many seedlings. The researchers incorporated the fuel loading into their fire behavior calculations and found that sometimes it added more to the surface fuels than dead wood. There was an overall reduction of fine surface fuels in logged stands, especially the burned units, which would reduce the spread of surface fire. It was more likely that a surface fire would transition to the crown on treated plots, but crown fires were less likely to spread in treated plots compared to the untreated plots. In conclusion, cutting and burning treatments in lodgepole pine forests can create complex structure in lodgepole forests and promote resilience to wildfire.

Forest Service Partners

External Partners

  • Joel Egan, Entomologist, Northern Region, Forest Health Protection
  • University of Montana College of Forestry and Conservation?