Wild forests fare better under fire

A University of Montana study about the connection between logging and wildfires ratifies what many firefighters have long held as a truism: In Ponderosa pine and mixed conifer, fires tend to be hotter and nastier on logged ground than in unlogged forests.

The study design used pairs of forest stands, one logged, one unlogged old growth. The forests were Ponderosa pine and dry mixed conifer and they were chosen based on their lack of recent fire history and similarities of slope, soil type, elevation and other physical factors.

The study found that the density of small trees was more than double on logged sites. Populations of the relatively fire sensitive Douglas-fir were much higher on the logged sites. In brief, logged stands showed “strong dominance of small fire-intolerant trees in overall stand characteristics of logged sites.”

The authors conclude that to the extent that modern wildfires are driven by vegetation and fuel characteristics, historically logged stands are more likely prone to severe, stand-replacing wildfires than unlogged, fire-excluded stands.

Similar results were found for ponderosa pine plantations in California (Fire Science Brief, issue 56, July 2009. Learn more at firescience.gov). According to that brief: “Ponderosa pine plantation forests cover nearly 400,000 acres of California’s National Forests. Fire hazard is extreme both within and adjacent to many of these areas, which has led to extensive fuel reduction plans for plantations and other forests on federal public lands.”

We continue to see that far from always being a solution to fire problems, logging is often part of the cause of fire problems.

TWS Fire Program Associate Rich Fairbanks spent 32 years with the Forest Service, serving a dozen of those on fire suppression crews.

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