Fuel reduction projects are designed to reduce wildfire hazard, but goals can also include ecological restoration, wildlife habitat enhancement, and forest health improvement. In the U.S. northern Rocky Mountains, ponderosa pine/Douglas-fir forests cover over eight million hectares (≈20 million acres). Before European settlement, these forests burned very frequently (3-30 years) mostly as low-intensity fires. A century of fire suppression policies has converted many open, seral ponderosa pine forests to dense stands with abundant Douglas-fir regeneration, resulting in reduced tree vigor, increased susceptibility to insect infestations, and increased fire hazard, even for older, traditionally more fire-resistant trees.
The USDA Forest Service began harvesting timber from the Lick Creek drainage on western Montana’s Bitterroot National Forest in the early 1900s. This early work was documented in photographs, which have been replicated for over 100 years. The photographs show changes in forest stand structure in the absence of disturbance, such as fire and harvesting, and helped demonstrate the need for restoration research in northern Rocky Mountain ponderosa pine forests. Thus, the Lick Creek Demonstration–Research Forest studies were established in 1991 to evaluate tradeoffs among alternative cutting and burning strategies aimed at reducing fuels and moderating forest fire behavior while restoring historical stand structures and species compositions. The experiment consisted of two separate studies of thinning and retention shelterwood cuttings with and without prescribed burning treatments (Figure 1). Treated units were harvested in 1992; half of the units were prescribed burned 1 to 2 years later. Throughout the 23 years since treatment, effects on the forest ecosystem have been studied, including: fuels, forest structure and composition, understory species responses, tree physiology, resistance to bark beetles, carbon storage, and fire hazard. Permanent photo points established in each study also visually document forest and fuel change over time.