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  • Peter Bane, Publisher Emeritus

Building Forest Resilience: Facing the Fire

by Peter Bane OF THE FOUR HORSEMEN of the Climate Apocalypse: fire, flood, storm, and drought, fire—despite its fearsome visage and unflinching finality—may be among the most susceptible to human influence. We have, after all, been working with fire, to our advantage more often than not, for more than a million years.

Worldwide, wildfire is a phenomenon of the edge between nomads and civilization, with 8 of 9 wildfires started by human-caused ignition. (1) Lightning does start fire, but despite tropical regions receiving many more lightning strikes than other areas of the globe, the worst fires, historically, have burnt in coniferous forests of the boreal and cold temperate zones. The 1871 Peshtigo fire in Wisconsin (1.5 million ac), was overshadowed by the even more famous Great Chicago fire occurring on the same night, but the Peshtigo blaze killed about 1,200 people, may have spawned fire tornados, and jumped 10 miles over the open water of Green Bay to the Door Peninsula. The 1910 Big Blowup igniting in Montana (3 million ac) and the little known but colossal 1987 Black Dragon Fire of Manchuria (18 million ac straddling the Amur River in China and Soviet Siberia) (2) suggest the potential scale of wildfire calamity where seasonal or multi-year droughts have created conditions for conflagration.

The climate challenge in the West

Kiln work shows flame top reduction of biomass to char. Photo by Joanna Dudley.

Wildfire is not confined to any one North American region, but it dominates chiefly in the arid and semi-arid West. The Great Lakes region has a fire season—it was especially bad in the Spring of 2021 in Wisconsin, with 1,500 acres alight by April—but these smaller outbreaks have been dwarfed in recent years by the gigantic fires of California, Oregon, Colorado, and other western states; some exceeding 200,000 acres. Collectively, these latter are causing annual damages estimated to range toward $200 billion in total losses, of which only 10% may be insured. Firefighting costs in 2020 ran over $2 billion, a heavier than average figure (2) with insured losses between $7-13 billion (3), but the loss of wildlife, soils, and public peace of mind are not quantified. The added costs of healthcare, early death from smoke inhalation, and a thousand other cuts are hidden from view by our peculiar systems of accounting. A panel of experts estimated that in 2018 alone, California sustained $148.5 billion in losses; consisting of capital losses, business disruption costs, and added healthcare burdens. (4)

Two major factors widely acknowledged to contribute to the increasing danger of wildfire are first, the history of fire suppression, a once noble objective that grew out of the nation’s horror at the 3-million-acre Big Blowup early in the last century: it scorched large sections of Montana, Idaho, Wyoming, eastern Washington, and even crossed the international boundary into B.C. With its devastating loss of timber, it was viewed—in the ideology of the day—as akin to a bank robbery, only of natural resources—read ‘lumber and profits.’ The enduring response to suppress fire was rational at the time, though ill-informed about ecology and fire dynamics, and it went on far too long in an era of fossil-fuel invincibility (we beat the Germans—twice, we can beat fire). The result of this has been increasing loads of hazardous fuel over larger and larger areas. This means larger and more devastating crown fires, where small fuels on the ground and dead branches on too many stems result in laddering, rapid fire spread, and even fire storms and fire tornados. The second factor also grows out of technological hubris, but on the water side of the equation: expanding settlement around Western cities, into a region known as the Wild and Urban-Interface (WUI, becoming its own word as all good acronyms do, something like ‘whooey’). Whoohee indeed! More suburban houses, more exurban homesteads, more road cuts, more careless cigarettes, downed powerlines, chains dragging below trucks, campfires, bonfires, barbecues—you name it: we burn it. Massive hydraulic projects moving water over subcontinental distances, even over watershed divides, have provided drinking, bathing, car washing, and industrial water for millions who sought the sun and the healthful dry air of the western Sun Belt. This expanding edge, so fruitful in ecosystems, has brought human fire into intimate contact with vast areas of woodland throughout the West.

I identify this mass migration toward the sun, and the agricultural expansion which preceded it by a generation, as hubris, because the unconscious and unlimited pursuit of a good thing has created many bad things, and those bad things are undoing the good ones. Climate change, in large part a result of our patterns of settlement—with US consumers driving more and larger cars and trucks for decades on end to reach these suburban would-be paradises—has pushed planetary heating, and consequently the drying and draining of the great federal Reclamation project that built Hoover Dam and all the rest. The hydraulic civilization of the North American West, like so many before it, is threatening to come undone.

So, there you have the problem in a nutshell.

  1. We thought nature was a bank account, and resented that fire was making unauthorized withdrawals, so we tried to stamp it out. We succeeded until we’ve almost failed.

  2. Into this bright, green, empty, irrigated, and enticing realm thus created we moved in our millions, and built sprawling suburban settlements that required driving from home to work and back. Indeed, it required driving to everywhere, since we did no rational, walkable urban planning until quite recently. The automobile drove highway construction, and highways made the automobile unavoidable. Once a landscape is built, it’s very hard to change. Seventy percent of the surface area of the Los Angeles metropolitan region is given over to car-dominated spaces—roads and parking lots. (5) There’s no place left to walk.

  3. The sprawl ate into the woods. Sprawl was drawn toward it by cheaper land and the ever-receding goal of living close to nature-as-object. The sprawl also heated the atmosphere from widespread pavement and fossil fuel burning writ large. This in turn dried out the woodlands surrounding those new developments. The fragmented ecosystems that arose were ripe for combustion with tangled edges and a million sources of ignition from angry and careless nomads racing around at high speed on their iron ponies.

Changing the dynamic

This certainly seems like a vicious and degenerative spiral, but there are some signs of hopeful change. The Great Recession put a kind of halt to suburban expansion in many places where it couldn’t be sustained without cheap fossil fuels. In the long term, that trend continues. Oil prices are on the rise again, and we are now beginning to understand not only that fossil energy consumption drives climate disruption—scourging us with ever higher insurance costs, and catastrophes that verge on the apocalyptic; but it also undermines democracy, most directly and obviously by funding sociopathic autocrats and would-be autocrats around the world.

Demographically, the ever-growing wildfires are themselves pushing back. At least some people were persuaded that the sunny (and arid) West isn’t all the wonderland it might once have been. California’s population shrank for the first time in history last year.

In the ecological realm, public land managers are developing a new consensus that fire suppression, while it may be a necessary burden in the WUI for now, is not the right prescription for long-term management of forests that have always burned. How can these hopeful trends be encouraged, and what can we do to close the gap until we redesign our cities and our transportation and energy systems, and the climate cools?

Larger stems too large for the kiln but laid on contour retain biochar against runoff, also trapping sediment and moisture.

Learning preventive maintenance

Fire control is always more effective and less costly when done in advance, so state and federal agencies charged with reducing wildfire risk have long encouraged homeowners, farmers, ranchers, and private woodland owners to create “defensible space” around their homes, and to reduce excess fuels by limbing, thinning, and removing the legacy of neglected and accumulated underbrush. They’ve done so with inducements of $800-$1000/acre in reimbursements to property owners who undertake this work. The typical disposal method for the trimmed and cleared biomass is pile burning.

This is laudable, but until recently has been underfunded and wholly inadequate to the scale of the threat; it also creates its own set of problems. As rapidly increasing wildfires are filling Western skies with smoke for longer and longer periods, killing thousands and tens of thousands each year from respiratory-related ailments (6), pile burning, though typically done in cool seasons, has become an unwelcome addition to the sometimes-intolerable conditions of many western regions in warm weather. “What! The air finally cleared from all those wildfires, and you want to burn more!” Paradise, and not just the ill-fated California town, is going up in smoke.

We could be stuck between a rock and a hard place, unable to afford reducing the patently obvious risks, and unable to live with them, but bear with me. Some modest technical innovations, resting on the discovery a few decades back, of some remarkably fertile soils in the Amazon, point to a possible pathway out of our dilemma.

Biochar & the psychotrope of altered climate

I have to preface what follows with the caution that climate apocalypse has put most of us into some degree of trauma. This arises from a foreboding sense of helplessness, and has many expressions: avoidance, denial, depression, anger, reaction against palliative efforts, even blaming experts, who of course didn’t create the problem but had the audacity to name it and attempt to measure it. You’ve seen examples of all these played out in the public sphere for the last 30 years. Some people have simply given up and turned away. That won’t spare them the effects of the crisis.

If, as I see it, the immediate threat to life, property, and stable societies (in the North American West) is rampant and increasing wildfire, and the drivers of wildfire—climate-induced drought and the chaotic intrusion of humans into the wildland-urban edge—aren’t subject to a rapid turnaround, but will likely require decades to remediate; then the only thing we can do, the only thing we can afford to do right now and for the next generation at least, is to reduce fuel loads everywhere, and to do so without wanton burning.

So, what would that look like?

Finding a way forward

Researchers within and outside of academia have been experimenting with pyrolysis, the making of charcoal from brush and waste wood in a limited oxygen environment, as a means of reducing fuel loads without returning carbon to the atmosphere (or much less of it). Counter-intuitively, this “burning” process sequesters carbon that would otherwise drive CO2 levels higher. It uses combustible elements in biomass to stabilize the remainder. It’s a kind of ram-pump process for carbon, burning a little to save the rest. (7)

The discovery, beginning in the 19th century, but accelerating in the last decades, of terra preta, or ‘dark earth’ in the Brazilian Amazon, Central America, and elsewhere, and the puzzling out of where it came from, has led to a worldwide interest in biochar or bioactive charcoal.

Terra preta was human-made hundreds of years ago by the agriculturally expansive civilizations of the Amazon basin and other regions of the Americas. They made it to build enduring soil fertility in ecosystems where soils were heavily leached by heat and torrential rains. By heating waste biomass, bones, even pottery shards, in the absence of oxygen, these early farmers created charcoal, which retained the complex and open cellular structure of its original material. Into these myriad micropores, water, nutrient, and soil life would seep or adsorb or swarm, and cling tenaciously, much as they do to humus and other forms of stable organic matter, greatly augmenting fertility in the surrounding soils. A half millennium after these peoples disappeared, the dark earth soils testify to their innovative farming methods. (8)

Kelpie Wilson instructs FERP crew in kiln assembly and loading. Photo by Karen Taylor.

The notable quality of biochar that distinguishes it from organic matter or humus is biochar’s durability over very long periods, centuries to millennia, even in the face of tropical heat and downpours that leach nutrients from the native equatorial soils, and otherwise burn up organic carbon.

Design features of biochar

Soil scientists, permaculture designers, and a host of other inventive people have been searching for the right ways to make and use biochar for more than 20 years, and quite a bit has been learned:

Carbon sequestration - Up to 50% of the carbon in biomass can be stabilized and held in biochar. (9)

Nutrient retention - Plant roots seem to seek out biochar where it is placed in soils; the surface area of biochar is immense. It has been likened to a coral reef in the soil. Its negative charge attracts the positive charge of nutrients. Mineral ions cling to it and microbes find the protective habitat quite hospitable.

Water holding - For the same reasons of abundant pore space and negative charge, water is attracted and held in a way that plant roots can access, but which resists desiccation by drought.

Recalcitrance - Carbon may be labile, easily sliding into other forms, including CO2 , or recalcitrant, and the degree of that hardness or durability is somewhat related to thermal and gaseous conditions of burning or pyrolysis. The good news is that new kiln designs produce strongly durable carbon, but also, a range of types of biochar, produced by imperfect methods, is nonetheless helpful in supporting soil life diversity. Essentially, any type of biochar is good in soils. Forests, by burning, have been making their own for millennia in fire-adapted ecologies.

Methods of making - Traditional charcoal making focused on the end product, whether cooking fuel, charcoal for industry, or artist material, with little concern for air pollution, and an emphasis on long and drawn-out smoldering. It was a dirty and unhealthful industry, even when done with care. New kiln designs adapted to the Western fuel crisis have emphasized low emissions, portability for ease of onsite production, and careful controls on oxygen. The results are counter-intuitive but effective: a top-lit kiln flame moves downward; carbon moves toward the ground and stays put.

The flame-top innovation

The most important breakthrough in kiln design in recent years centers on what is called “flame-top” or “flame-cap” burning. Fuels are packed into an open-topped steel kiln, often with double walls that both insulate—holding in heat for more efficient pyrolysis—and direct air from ground level up between the two walls to the top edge of the open kiln. The resulting flow of preheated air, and top lighting of the fuels results in a flame that often curls into the kiln, and which consumes all or most of the volatile gasses released during the early phases of charring. More fuel can be added once the first has been lit; monitoring is easy.

The radiant heat of the first gasses combusting on top, chars or pyrolyzes the fuels below. As they release more gasses, instead of spewing smoke, these are consumed by the flames above without producing pollution, while the exclusion of oxygen from the lower levels of the kiln ensures that little of the actual solid carbon is burnt.

Single-piece kilns, often larger and suitable for long or bulky woody material, much like a dumpster body, or some in the shape of a shallow dish but still draggable by two people, the so-called “Oregon kiln,” are used for a variety of applications, but innovative designs made from steel panels, whether rigid or flexible, that can be easily ported into back country, and then quickly assembled and broken down, open up new vistas in fuels reduction for huge areas of the West.

Creating a system that can spread

Permaculture Institute of North America (PINA), through its Fire Ecology Restoration Project (FERP) is working with four private landowners in two regions of western and southern Oregon subject to intense fire risk, to answer a range of questions about methods and costs of using portable kilns to produce biochar in the woods.

Our working hypothesis assumes that biochar will improve forest soils and long-term forest health, so we redistribute the char made from limbing and thinning of overly dense forest stands directly back to the forest floor. We are also using recognized methods of placing the larger stems, which are unsuitable for the kilns, on contour to aid in holding water and sediment on slopes. The thinning process models conventional fuels reduction up to the point of disposal. Instead of pile burning, we reorganize the larger biomass to hold moisture, and we char the smaller material to create a valuable soil amendment that enhances water and nutrient retention.

These ideas are simple, but the economic equations are not, and this is the thrust of our rese