Science Findings, September 2008, Issue 106. Fuel Reduction and Forest Restoration Treatments: Once is Not Enough

摘要

Frequent, low-intensity fires were historically a common feature in many dry forests of the United States. Today, largely owing to fire exclusion and past management practices, many of these fire-dependent forests contain significantly more small trees and fewer large trees than occurred under the natural fire regime. These altered conditions increase the probability of unnaturally severe wildfires, susceptibility to uncharacteristic insect outbreaks, and drought-related mortality. Restoration of these forests is a priority for forest managers throughout the country. Unfortunately, little information exists about the effectiveness or ecological consequences of commonly used fuel reduction and forest restoration strategies. In response, a national research project called the Fire and Fire Surrogates Study is conducting operational-scale experiments to evaluate restoration treatments at 13 sites across the country. As part of this study, researchers working in dry, low-elevation forests in northeastern Oregon evaluated several fuel reduction and forest restoration treatments: a commercial thin, a prescribed burn, and a combination of the two. Thinning and the combination of thinning and burning reduced the density of live overstory trees, and burning and the combination of thinning and burning reduced the density of small-diameter trees.