Fire is a potent and powerful force of nature.
It is both terrifyingly regular and heartbreakingly unpredictable.
It inspires awe, and wonder, and fear.
It warms the body and soul.
And it can regenerate life.
Like water or wind, fire has its place in healthy natural systems. It’s as important to forests as rainfall, enriching soil, hastening the spread of seeds, letting in sunlight and refreshing habitat for diverse organisms.
But drier climates and an overabundance of potential fuel have changed the impact of fire around the world, and it’s changed how wild animals interact within natural systems.
In North America, birds like white-headed and red-headed woodpeckers, mountain bluebirds, and Kirtland’s warblers have tied their life cycles to the natural rhythm of wildfires.The black-backed woodpecker has too.
Like its cousin the three-toed woodpecker, the black-headed woodpecker is a resident of conifer forests across the northern U.S and Canada. It’s a post-fire specialist that relies on fresh burns for food and nesting habitat both black-backed and three-toed woodpeckers swoop into post-burn areas to gorge on the large grubs of beetles that infest the dead trees
Standing amongst the timber one can clearly hear the noisy chewing of the larvae as they gnaw at the wood beneath the still-clinging bark. Wood-boring beetles swarm in mass to burn sites, and immediately begin laying their eggs. The beetles are so attuned to zeroing in on burns that in the 1940’s, when public smoking was still allowed, they would descend through the hazy cloud of 20,000 puffing cigarettes upon University of California football games, “alighting on the clothing or even biting” spectators.
Black-backed Woodpeckers are a “keystone species” — an animal that other species depend upon for survival success. They excavate holes in trees that enable other birds and animals to claim once the woodpeckers are finished with them.
A new study published in The Condor offers proof that Black-backs do prefer nest sites within the scorched trunks of a burn site, but also within 500 meters of living forests where their fledged young find higher survival rates in the denser vegetative cover
However larger and hotter fires — called “mega-fires” — are affecting the way these woodpeckers access habitat across the western U.S. Because of climate change, fires are burning hotter, without leaving behind burns diverse in age, size, and severity. This reduced pyrodiversity is less supportive of a rich variety of living inhabitants.
As severe fires engulf large swatches of western forests, the woodpeckers are pushed farther out toward the edges of burn areas. It creates immense, less accessible territories, complicates the birds’ nesting options, and thins their population density.
For decades across North America, fire suppression led to the build-up of dead and down wood fuel stores. Reduced precipitation and warmer temperatures have in turn set the stage for extreme fire conditions.
Even living trees have been scorched by climate change. A healthy tree is even more significantly affected by heat than by drought. During prolonged heat, a tree will “hold its breath,” by closing the stomas on its needles to prevent the loss of moisture.
But this process also means that the tree cannot effectively photosynthesize, and over time it can become stressed beyond recovery.
Pine bark beetles have also ravaged weakened conifer trees in the West, leaving them vulnerable to fire.
And smaller brush fires that once spared old venerable trees are now being usurped by crown fires that devastate old growth and allow for accelerated erosion and the of exotic plant invaders.
The black-backed woodpecker is symptomatic of the dilemma that climate change presents. The bird historically benefits from fire, but those habits are complicated by some of the largest and most damaging fires the American west has ever experienced.
Earth’s systems are fined-tuned mechanisms that have evolved over millions of years, but climate change is altering how those systems function. Stewards of public and private forests across North America face the challenge of both understanding how climate change affects biotic systems, and how to best manage natural resources.