By Dr. Robert Thorson

Who’s to blame for California’s deadly Esperanza wildfire? Was it the arsonist who allegedly set the blaze? Or was it a land-hungry public so desperate for housing lots that they built directly in harm’s way?

It was the latter. If building on steep slopes invites landslide damage, and if building on beaches invites storm damage, then building anything but asbestos houses in California’s chaparral country is an accident — that really isn’t an accident — waiting to happen.

The media story was an emotional firestorm. It took off with dramatic visuals of leaping orange flames, pillars of smoke and battlefield bravery. It continued with the manhunt for a convicted pyromaniac. It ended with heart-tugging memorial services for the dead. But the scientific story behind the media story wasn’t told at all, perhaps because it involves evolution, in this case the creation of chaparral, a fire-adapted ecosystem dominated by a mixture of drought-adapted evergreen oaks, brush, herbs and grass.

“In a sense,” concludes the writer John McPhee, “chaparral consumes fire no less than fire consumes chaparral.” This plant community has “an always developing, relentlessly intensifying, vital necessity to burst into flames.” Otherwise, its seeds won’t sprout, organic nutrients won’t rejuvenate new growth, and fresh soils will not be exposed. Fire is so essential to chaparral that its plants have evolved waxy resins and flammable solvents that make them burn as if drenched by gasoline.

And, to make matters even more incendiary, southern California is fanned by Santa Ana winds draining down from the cool high mesas of the Colorado Plateau. As they head westward, they dry, pick up speed, and become gustier. By the time they reach places like Esperanza, the air is so parching that it creates an instant fire danger. “Moisture,” as McPhee writes, “evaporates off your eyeballs so fast you have to keep blinking.”

Under such conditions, a single match or errant spark is not so much the cause of a blaze than its trigger, more like the detonator on a weapon of mass destruction than the bomb itself. Building homes in such a predictably flammable situation is like building them on the grate of a kindled fireplace being blown by a hair drier.

Construction also commits the U.S. Forest Service to behave more like a commando-style fire department than a prudent group of ecologically oriented fire managers. For there is no threat at all until the homes intrude. Then, with public safety being threatened, there is no choice but to send in the troops at the first sign of smoke.

In the Esperanza case, this meant 2,500 firefighters being paid at public expense, five of whom died in action, despite their bravery, skill and commitment. Altogether, more than 40,000 acres were charred, $10 million was lost, more than three dozen homes burned and many lives disrupted.

And for what? For a mundane fire, one of an endless series that burn their way across southern California with a regularity not unlike Gulf Coast hurricanes.

If only the ecological foresters were allowed to be in charge, rather than their quasi-military counterparts. Then fire could be seen as the indispensable landscape process it really is.

Consider the glorious autumns of northeast North America, when leaves “fall” to the ground on an annual schedule. The northeastern forests can get away with this seemingly wasteful process because there’s always enough moisture to recycle nutrients back to the soil. In chaparral, however, the soils are too dry for decomposition to be effective. The litter thickens, year after year. Standing dead brush becomes denser.

“Fall” in this kind of country happens only when the ash from burnt biomass descends to the soil. Fire is a good thing. It brings on the fall.

The Esperanza disaster began not with an arsonist but with the voter-taxpayers who misunderstand fire. People need places to live. Local communities need tax dollars. House lots are approved in flammable places that rely on the subsidized protection of the firefighting arm of the U.S. Forest Service.

The human tragedy of the Esperanza wildfire is real. But beneath that disaster is a very happy soil. “Fall” has arrived. Spring will commence with the first soaking rain.