This year, as in every year, fires are occurring in the forests of the western United States. And, as always, we read the predictable headlines about how many acres of forest were “destroyed,” whether in Yellowstone National Park in the famous 1988 fires or today’s Rim fire in the Stanislaus National Forest and Yosemite National Park.
Some claim more logging is needed to “salvage” dead and dying trees and “rehabilitate” burned landscapes, and many complain about the smoke. But the central questions remain: Does fire harm forests and what remedial actions are needed, if any? Is the system out of whack due to fire suppression and global warming? As fire ecologists, we have spent years studying the aftermath of forest fires and the wealth of life that exemplifies nature’s healing powers.
Bordering on some of California’s giant sequoias, the Rim fire is more than 255,000 acres in size, and has been consistently described as “catastrophic,” “destructive,” and “devastating.” It turns out that this fire is actually ecologically restorative. And, while it may kill some of the sequoias, large sequoias are highly resistant to fire, and sequoia regenerates most vigorously after intense fire turns understory brush and twigs and needles on the forest floor into useable nutrients.
Soon after the fire, native wood-boring beetles will rapidly colonize the standing dead trees, detecting fires from miles away through infrared receptors they evolved in a long relationship with fire. The beetles bore under the bark of trees, and their larvae provide a food source for the rare and imperiled black-backed woodpecker – a keystone wildlife species that, every year, creates new nest cavities in fire-killed trees, providing homes for many other cavity-nesting wildlife species. Within years, the regenerating sequoia forest is a symphony of bird songs, punctuated by colorful butterflies and dragonflies, flowering plants, and a carpet of conifer seedlings that is anything but a disaster.
Contrary to what many may think about fires in Yosemite or elsewhere, there are far fewer of them in forests today than there were before European settlers arrived. Over the past few decades, fires have increased in size in some areas, but still remain well below what American Indians witnessed historically. Today’s climate scientists investigate whether fires are burning hotter than they once did; however, using decades of satellite images and pollen records that date back to the last millennium, we and other scientists have yet to see an increase in the severity of forest fires in the Pacific Northwest or Sierra Nevada. It is possible that global warming could lead to more fires in the future; however, some computer models predict increasing summer precipitation in these regions.
After fire, logging can damage the restorative powers of a forest by compacting and eroding life-giving soils, removing large trees that anchor fragile soils and shade new seedlings, taking big fire-killed trees that provide irreplaceable habitat for wildlife, and crushing conifer seedlings as logs are dragged uphill. Consequently, natural areas should be allowed to regenerate on their own as they have for millennia.
It is time we had a rational discussion on the proper role and management of wildland fire in forests, lest we continue to mislead people about the ecological role of fire and what to do about containing fire. Putting out fires close to homes is a matter of public safety, but attempting to squelch them in the backcountry is unlikely to succeed, as most large fires are put out by nature when it rains. Fundamentally, we need to develop a new way of discussing forest fires – one that recognizes what the current science is telling us: that post-fire habitat is as ecologically rich and diverse as old-growth forests, yet it is the rarest and least protected forest habitat type in the Sierra Nevada.
Dominick DellaSala is an award-winning science author and chief scientist at the Geos Institute in Ashland, Ore. Chad Hanson, based in the San Bernardino Mountains, is the director and staff ecologist of the John Muir Project of Earth Island Institute.