Working paper 27: Fuel treatment longevity.

Dry forests of the western United States have been altered by long-term fire exclusion, resulting in a more dense forest structure and an increased risk of crown fire. Recently, thinning and prescribed fire treatments have been implemented in these forests for two main reasons: ecological restoration and fire hazard reduction. Ecological restoration is a holistic endeavor that focuses on restoring ecological patterns, processes, and functions. Ecological restoration goals often include restoring the process of fire to forested ecosystems and changing forest structure to fall within the historical range of variability as indicated by reference information. While fire hazard reduction is often a goal or an outcome of ecological restoration, not all treatments specifically designed to reduce fuels also restore ecosystem patterns, processes, and functions (Reinhardt et al. 2008). Fire hazard reduction treatments are designed specifically to reduce fire intensity, reduce fire severity, and increase the ability of firefighters to control wildfires (Table 1). Fuel treatments are common and are generally regarded as beneficial for reducing fire behavior, as well as for ecological reasons such as increasing understory diversity and reducing competition among trees for nutrients and water. What remains unclear is how long such fuel treatments are effective in reducing undesirable fire behavior. This working paper addresses the following management questions regarding fuel treatment longevity: What factors influence fuel treatment longevity? How long will fuel treatments last before sites need to be retreated? Do some types of treatments last longer than others