Some 102 million trees have died in California since 2010, and that number will likely grow. Dead trees in a forest are natural, but the extraordinary numbers we see in parts of the Sierra Nevada threaten many benefits of our forests. Some places that had 20 trees per acre a century ago now have 260 trees.
Too many trees, dead or alive, produce too much fuel. Once a fire gets started, a continuous expanse of fuel makes it more likely the fire will become extreme. California’s wildfires affect the whole nation. A recent study found that California consumes nearly half of all western wildfire costs. Too many lives are lost and homes burned. Wildfires destroy wildlife habitat, and pollute water with sediment and fire-fighting chemicals. Sediment reduces reservoir capacity. Landscapes scarred by large wildfires take generations to heal.
Paradoxically, wildfires also threaten California’s leadership in addressing climate change. One big wildfire can release massive amounts of greenhouse gases.
To reduce both wildfire risk and tree mortality, we should remove excess trees but do so in a particular way. Scientists have developed a promising strategy that focuses on the pattern of trees remaining after harvest. Big, old trees are untouched, and many small trees are removed. The result is a more variable forest with more open space.
Loggers, environmentalists and governmental agencies used this strategy in the 9,000-acre Sagehen Experimental Forest near Truckee, and all benefited. Loggers got wood for manufacturing. Environmentalists got improved wildlife habitat.
The good news for the rest of us is that this new tree pattern makes forests more resilient to fire, insects and drought. With fewer trees, fires tend to remain low to the ground and are controlled more easily. Under certain conditions, they may extinguish themselves. Such ground fires clear out underbrush and use up excess fuel.
Applying the Sagehen strategy to millions of acres in the Sierra could safeguard the many benefits of forests, reduce the cost of fighting fires and would save lives and homes, fish and wildlife, and scenic vistas and recreation areas.
The new approach could also support California’s fight against climate change. Healthy forests absorb carbon more quickly and release fewer greenhouse gases. Like Europeans, we could build 20-story buildings out of innovative wood products, locking up carbon otherwise released by wildfires.
We have a choice. We can continue business as usual and accept ever-larger wildfires that escalate damage to lives, property and the environment. Or we can use this alternative approach that will save taxpayers substantial amounts of money and ensure our grandchildren will inherit healthy forests.
Amy Horne is chairwoman of the Lahontan Regional Water Quality Control Board, though her views do not reflect those of the board, and can be contacted at Amylou.Horne@gmail.com. Jim Branham is executive officer of the Sierra Nevada Conservancy and can be contacted at firstname.lastname@example.org.