Pacific Rivers Council Releases Science Report On Watershed Impacts Of Fuel Treatments

The Pacific Rivers Council has released a study that analyzes the harmful watershed effects caused by forest fuel treatments. "The Watershed Impacts of Forest Treatments to Reduce Fuels and Modify Fire Behavior," authored by independent hydrologist Jonathan J. Rhodes, raises serious questions about the ecological efficacy of forest thinning and other mechanical fuel treatments intended to control wildfires - primarily because of their unintended but inevitable damage to forested watersheds.

The impacts of mechanical fuel treatments on watersheds are especially of concern because aquatic systems are significantly and pervasively degraded, and many populations of aquatic species (including native trout and other salmonids) are highly imperiled or have experienced severe declines. Additional damage to aquatic systems from these treatments further reduces the prospects for their persistence. In some instances, fuel treatments actually work against watershed restoration needs because of the practices involved and the diversion of resources away from beneficial restoration activities, such as road upgrading and removal.

The peer-reviewed report finds that the ecological costs of extensive thinning and other treatments are virtually inevitable: first, because many proposed projects necessarily involve repeated entries into the same area, which raises the scale of cumulative effects and effective level of disturbance; second, because the treatments cause direct impacts (e.g., they damage soils, cause erosion, disrupt streamflows, and damage riparian areas); and third, because the treatments fail to address the actual dominant causes of watershed degradation, such as road building and grazing. Combined, these factors can impede or set back ecologically sound efforts at aquatic ecosystem restoration.

Based on a detailed statistical analysis of a large body of fire data spanning many years, the report finds that mechanical fuel treatments are extremely unlikely to reduce the intensity of so-called catastrophic fires. In addition, the analysis finds that only in a small number of cases would treated areas likely be in the path of intense fire over their intended lifetimes (i.e., the period of time after treatment when fuels are reduced).

The report concludes with a precise set of recommendations to reduce the ecosystem damage from mechanical fuel treatments, including limiting treatments in the most sensitive portions of watersheds and prohibiting the most destructive fuel treatment activities.