The timber industry and the U.S. Forest Service aggressively market the idea that reducing fuels through logging/thinning programs will result in a significant decrease in acreage burned, firefighting costs and the number of high-severity fires.
However, it is climate/weather, not fuels, that drive all large wildfires.
The factors responsible for all large wildfires are drought, low humidity, high temperatures and, most importantly, wind. If you have those ingredients in the same place with an ignition, you get a wildfire that can’t be stopped — until the weather changes.
The recent extreme drought that gripped California was the biggest factor in creating the ideal conditions for large, high severity blazes.
The very fires that logging/thinning programs seek to control and stop are the wildfires burning under extreme conditions that cannot be controlled through fuel reduction efforts. These wildfires are few in number but are responsible for the vast majority of all acreage burned annually.
For instance, a total of 56,320 fires burned over 9 million acres in the Rocky Mountains between 1980-2003. Approximately 98 percent of these fires (55,220) burned less than 500 acres and accounted for 4 percent of the area burned. By contrast, Only, 2 percent of all fires, burning under extreme weather conditions, accounted for 96 percent the acreage burned. And 0.1 percent (50) of blazes were responsible for half of the acres charred.
Furthermore, the probability of a wildfire encountering a fuel reduction is very small, even if they did work as some suggest, making most fuel reductions essentially useless but still leaving behind the negative impacts of logging on soils, watersheds, nutrients, carbon storage, wildlife habitat losses, and consequences like spread of weeds, sedimentation from roads into streams and so on.
Plus, there is evidence that timber management (i.e. logging) can increase fire severity. A recently published study concluded: “We investigated the relationship between protected status and fire severity applied to 1m500 fires affecting 9.5 million hectares between 1984 and 2014 in pine (Pinus ponderosa, Pinus Jeffrey) and mixed-conifer forests of western United States. … We found forests with higher levels of protection had lower severity values even though they are generally identified as having the highest overall levels of biomass and fuel.”
The Congressional Research Service reached a similar conclusion. “From a quantitative perspective, the CRS study indicates a very weak relationship between acres logged and the extent and severity of forest fires. … The data indicate that fewer acres burned in areas where logging activity was limited.”
These studies suggest that thinning/logging is a very inefficient and ineffective means of altering wildfire behavior — especially under extreme fire weather.
By contrast, study after study has concluded that protecting homes is best accomplished by reducing the flammability of the structures, not logging the forest. As one study asserted. “It is the treatment of the fuels immediately proximate to the residences, and the degree to which the residential structures themselves can ignite that determine if the residences are vulnerable.”
George Wuerthner is an ecologist who has published 38 books including two dealing with fire ecology and five dealing with California parks and wilderness.