One of the most-apocalyptic images from California latest round of fires is flames glowing from inside a tree trunk inside California’s first state park. It seems outlandish, even demonic.
In fact, it’s so routine that there’s a name for the hollow space a fire leaves in the base of a coastal redwood: a goose pen. Early anglo-American settlers used the abundant cavities to shelter their livestock. Most redwoods with goose pens are still alive.
From the perspective of a redwood grove, a fire is not terribly threatening. The trees have an arsenal of defenses: high levels of tannin, a natural fire retardant; bark that is thick (up to one foot!) and insulates living cambium; a towering canopy, which keeps foliage mostly clear of flames; and if the flames do reach it, epicormic (dormant) buds, poised to send new branches sprouting from the trunk.
In California, we mostly don’t treat wildfires as problems because of trees, but because of people.
We measure fire impact in deaths of people, in property losses by people, in air quality for people and emergency room visits by people, and in the charring of iconic vacation destinations for people.
Take this photo from California’s Big Basin State Park triggering national grief. It show a landmarked New Deal-era park building, burnt to cinders, only the chimney left. It’s surrounded by large trees, still standing, many foliated, that forest ecologists expect to mostly survive.
“The idea that we would have fires in redwood forests is not crazy,” says Lenya Quinn-Davidson, an area fire advisor to the UC Cooperative Extension, and director of the Northern California Prescribed Fire Council. “In fact, it can be really healthy for those forests.”
Fires clear room for big trees to get bigger, burn off invasive species, create openings for natives, free up water for streams and aquifers (by killing thirsty scrub), even cool surface waters (with a sun-blocking screen of smoke) at precisely the time of year that cold-dependent salmon swim upstream to spawn.
Quinn-Davidson points to the Canoe fire, which burned 11,000 acres of redwoods — some up to their crowns — in 2003. “It’s a lovely place to go hike through now, it really opened things up and refreshed the forest.”
Fire as ecological maintenance tool is something California’s indigenous peoples understood. They let wildfires be, and managed frequent burns of their own. Quinn-Davidson says under indigenous fire management, coast redwood forests might burn once every 15 years.
The white settlers who drove them from most of their land proved less apt at fire management. They clear-cut forests, leaving them to grow back as crowded stands of trees, shorter and more fire-vulnerable. They suppressed natural fires, and outlawed traditional burns. They presided over a build-up of combustible debris and vegetation (“fuel load” to firefighters), that ensured fires that did break out got more intense. (Past a certain intensity, fire can do lasting harm, killing even the biggest trees, cooking soil sterile, setting the stage for mudslides.)
Reversing that is tricky. This month, California and the federal agencies that control most of its forested land agreed on a general plan of thinning forests, then doing controlled burns, over the next 20 years. (The details will get contentious: the plan includes “improvement” of California’s “sustainable timber harvest,” a job that will fall to timber companies more accustomed to maximizing board-feet than ecosystem health.)
Meanwhile, we keep building (and re-building) homes in places that like to burn.
Buildings, it turns out, do not fare well in fire-prone places. A mature redwood will shrug off all but the most intense blaze. But fell it, mill it, turn it into framing, siding, shakes and decking. . . it takes just one well-placed ember to light it like a torch. Close to a third of Californians now live in a place with wildfire risk. At great expense and effort, we have turned California into a place where fires burn less land, but do more harm (to people).
Climate change, of course, worsens things: California’s forests, particularly in the Sierra mountains, are stressed from years of drought, leaving stands of dead trees drying into tinder. Record-setting heat waves help fires burn hotter and spread faster.
But even absent climate change, California would face a reckoning over where homes should be allowed, and the cost of defending them (and where else to build housing in a state that doesn’t have nearly enough).
The first priority of California’s fire agency, CalFIRE, is saving lives. The second is protecting property. Every new property full of people living in a wildfire zone is a new people problem pulling wildland firefighters away from actual wildlands. Because wildfires, in California, are about people.
As I write, early in California’s fire season, this year’s fires have burned approximately one million acres. In 2018, a year of state and federal emergency declarations over wildfires here, the burn totaled 1.9 million acres. Using data from tree rings, charcoal deposits, and ethnographies, researches have tried to reconstruct how much of present-day California burned in an average year before 1800. Their estimate? 4.5 million acres.
UPDATE: An Associated Press team has hiked Big Basin State Park’s old-growth groves and confirmed the trees are alright.