Black-backed woodpeckers would face extinction without wildfires

By John Upton

Illustrated by Perry Shirley.
Illustrated by Perry Shirley.

This summer has been a tinder-dry scorcher in the American West, where climate change is being blamed for a horror fire season. Mountain snow is melting earlier nowadays and summers are getting hotter — and that perilous partnership is fueling a steady surge in the frequency and size of the region’s wildfires.

The infernos kill firefighters, destroy homes and damage public infrastructure.

But it’s worth remembering that fires are healthy and regenerative phenomena in many ecosystems — including those in the West.

Blazes clear out water-hogging undergrowth and provide blank slates upon which timberlands can grow anew, boosting forest biodiversity. Rugged pods that encase the seeds of some specialized plants open after fire, sowing the genesis of the next generation in fertile fields wiped clean of competitors.

It’s not just plants that have evolved to rely on fire. Woodpeckers, for example, can flourish in its wake. The black-backed woodpecker has a particularly specialized diet that leaves it dependent upon the charred aftermath of wildfires. The species feasts on the wood-boring beetles that proliferate in burned trees following blazes in Western American mountain-ranges.

Rim Fire
The aftermath of the Rim Fire, the fourth-largest wildfire in Californian history, photographed near Yosemite National Park in early September by San Francisco journalist Chris Roberts.

But us humans are not as fond of fire as are the beetles or the woodpeckers that hunt them. Public policy dictates that fires should be avoided and, if that fails, confronted without compromise. The practice of preemptively thinning out forests to reduce fire impacts, and the logging of forests after they burn, have both taken heavy tolls on the black-backed woodpeckers.

Populations of these birds have been harmed so severely by public policies of wildfire suppression that the federal government is reviewing whether genetically distinct populations in two regions should be added to its list of endangered species.

“This is the first time in the history of the Endangered Species Act that the government has initiated steps to protect a wildlife species that depends upon stands of fire-killed trees,” Chad Hanson, an ecologist with Earth Island Institute, said when the U.S. Fish & Wildlife Service announced the review in June.

A clean-up following the Rim Fire, making it more difficult for black-backed woodpeckers to inhabit this area. Photo by Mike McMillan of the U.S. Forest Service.
A clean-up following the Rim Fire, making it more difficult for black-backed woodpeckers to inhabit this area. Photo by Mike McMillan of the U.S. Forest Service.

Hanson coauthored research published in May in The Open Forest Science Journal that showed just how severely one of those two populations of woodpeckers, which lives in the Sierra Nevada and southern Cascade ranges of California and Oregon, has been affected by humanity’s wont to battle fire. Hanson and his colleague, Dennis Odion, obtained data from the government and from their own observations which they used to model the effects of typical wildfire suppression policies in the Sierra on the species’ habitat.

“A scenario based on thinning 20 percent of mature forests over a 20-year period, and post-fire logging in 33 percent of potential habitat created by fire, reduced the amount of primary habitat after 27 years to 30 percent of the amount that would occur without these treatments,” the scientists wrote in the paper.

“Our results indicate that conserving the distinct population of black-backed woodpeckers in the southern Cascades and Sierra Nevada and the biodiversity for which they are an indicator will require that more unthinned area be burned by wildfires and protected after fire as critical habitat.”

The following table was lifted from the paper. It compares the amount of black-backed woodpecker habitat available within a study area following 27 years of simulated fire suppression policies:

woodpeckers and fire

And this photograph of an acorn placed in the trunk of a Rim Fire-charred pine is an endearing reminder that wildlife perseveres following fire. Wild Equity Institute founder Brent Plater tells me it might have been put there by a squirrel or a scrub jay — but that it was most likely the handiwork of an acorn woodpecker. “Caching acorns in tree cavities is what they do for a living,” he said.

Photo by Chris Roberts
Photo by Chris Roberts