Fire exclusion policies have affected stand structure and wildfire hazard in
north American ponderosa pine forests. Wildfires are becoming more severe in
stands where trees are densely stocked with shade-tolerant understory trees.
Although forest managers have been employing fuel treatment techniques to
reduce wildfire hazard for decades, little scientific evidence documents the
success of treatments in reducing fire severity. Our research quantitatively
examined fire effects in treated and untreated stands in western United States
national forests. Four ponderosa pine sites in Montana, Washington, California
and Arizona were selected for study. Fuel treatments studied include:
prescribed fire only, whole-tree thinning, and thinning followed by prescribed
fire. On-the-ground fire effects were measured in adjacent treated and
untreated forests. We developed post facto fire severity
and stand structure measurement techniques to complete field data collection.
We found that crown fire severity was mitigated in stands that had some type
of fuel treatment compared to stands without any treatment. At all four of the
sites, the fire severity and crown scorch were significantly lower at the
treated sites. Results from this research indicate that fuel treatments, which
remove small diameter trees, may be beneficial for reducing crown fire hazard
in ponderosa pine sites.
Fire effects on Gambel oak in southwestern ponderosa pine-oak forests
