– by John Buckley, Executive Director, Central Sierra Environmental Resource Center
Over 13 years as a firefighter with the U.S. Forest Service, I worked primarily on hotshot fire crews. During those years I fought a number of the largest wildfires ever documented in California as well as many other wildfires elsewhere across the West.
For years I taught wildland fire behavior classes, helped ignite and manage prescribed burn projects, and spent entire summer/fall seasons (between wildfires) doing post-fire restoration work in recently burned areas.
From that experience, I can emphasize that fuel loading, fuel arrangement, continuity of fuel, and fuel moisture combine with fire weather, topography, time of day, and other factors to determine fire intensity. Put simply, the more dry fuel that is packed on moderate to steep hillsides on a hot summer afternoon when there are up-slope or up-canyon winds, the higher the likelihood that a wildfire will make major runs that kill a large percentage of trees that might survive a lower intensity fire.
Strategically planned biomass removal projects can reduce that build-up of excessive fuel.
Various groups over recent years have passionately attacked the removal of forest biomass and the burning of biomass chips at power plants with strident claims that carbon emissions are significant and that even low amounts of air pollution should not allow biomass plants to qualify as green energy. Such claims completely miss some important facts.
First, in national forests across the Sierra Nevada and elsewhere, tree density and the basal area of conifers far exceed the documented plot data that was taken a century or more ago in the Stanislaus Forest and other sample sites. Due to the accumulation of surface fuels, decades of fire suppression, and the selective removal of the biggest conifers, national forests have unnaturally high tree stocking and completely unnatural fuel loads. Small shade tolerant trees such as incense cedars and white firs now choke stands that were historically open with sun-loving pines and oaks. Fuel levels are extreme, which often leads to extreme wildfire impacts on the forest environment.
Unless science-based selective thinning treatments open up some portions of dense forest thickets, little sunlight can penetrate to the forest floor to benefit groundcovers, wildflowers, grasses, and other plants so vital for healthy wildlife habitat. Without selective removal of dense thickets of small, understory trees, fuel ladders will continue to dominate underneath the over-story trees that are vital for wildlife as well as valuable as scenic forests for recreation. The need to treat surface fuels and ladder fuels is tremendous.
In many areas prescribed fires can effectively consume portions of the dense brush and small tree understory. But in countless other areas, biomass removal is either the only solution or the only economic solution to deal with ladder fuels.
One critically important point often ignored by biomass critics is that in Sierra Nevada national forests, large quantities of branches and tops of logged trees are either spread out or piled up after thinning or salvage logging treatments on public forest lands. Almost always, if biomass removal of that fuel is not done, those piles or jackpot slash areas are burned openly in the forest. The fuel either burns with emission reductions in a biomass power plant or it burns with no pollutant controls in open forest burning. Carbon is released either way.
For 25 years our environmental center has been a leading voice for protecting at risk wildlife species on public forest land. Completely consistent with that strong defense of vulnerable wildlife, our Center endorses increased levels of biomass removal to reduce fuel loading and give over-story trees a better chance to survive the next wildfire. In our local region, due to the Forest Service implementing only a low level of thinning logging, prescribed burning, and biomass removal projects over decades, the truly gigantic Rim Fire burned more than 97,000 acres at high severity. Just recently I drove and walked through areas where three years after that fire, literally no conifers survived over many square miles. A far greater program of prescribed burning and biomass removal could have significantly reduced the ladder fuels that literally cooked not only the over-story trees, but also the cones needed to re-start a recovering forest.
As climatic trends result in longer fire seasons, hotter temperatures, and accumulating fuels, forest managers can control only one factor – fuel. By expanding biomass removal of a portion of the small trees and brush that create ladder fuels, forest managers can shift the forest back towards more natural mosaic conditions, while simultaneously benefitting local economies.
John Buckley is executive director of Central Sierra Environmental Resource Center (cserc.org), a non-profit organization working to defend water, wildlife, and wild places across the Northern Yosemite Region of California.