The western United States has experienced some extraordinarily large forest fires in recent years. Part of the reason is drought conditions that have left the landscape tinder-dry. But another part of the reason is a century-long legacy of shutting down forest fires–even controlled burns. The PERC Reports magazine considers the history and consequences in a symposium on “How to Confront the Wildfire Crisis” in the Summer 2022 issue.

For example, Brian Yablonski discusses the origins of the policy in “The Big Burn of 1910 and the Choking of America’s Forests.” He writes:

Record low precipitation in April and May [1910] coupled with severe lightning storms in June and sparks from passing trains had ignited many small fires in Montana and Idaho. More than 9,000 firefighters, including servicemembers from the U.S. Army, waged battle against the individual fires. The whole region seemed to be teetering on the edge of disaster. Then, on August 20, a dry cold front brought winds of 70 miles per hour to the region. The individual fires became one. Hundreds of thousands of acres were incinerated within hours. The fires created their own gusts of more than 80 miles per hour, producing power equivalent to that of an atomic bomb dropped every two minutes.

Heroic efforts by firefighters to save small mountain towns and evacuate their people became the stuff of legend. “The whole world seemed to us men back in those mountains to be aflame,” said firefighter Ed Pulaski, one of the mythical figures to emerge from the Big Burn. “Many thought it really was the end of the world.” Smoke from the Mountain West colored the skies of New England. In just two days, the Big Burn torched an unfathomable 3 million acres in western Montana and northern Idaho, mostly on federally owned forest land, and left 85 dead in its wake, 78 of them firefighters. The gigafire-times-three scarred not only the landscape, but also the psyche of the Forest Service, policymakers, and ordinary Americans.

After the Big Burn, forest policy was settled. There was no longer any doubt or discussion. Fire protection became the primary goal of the Forest Service. And with it came a nationwide policy of complete and absolute fire suppression. In the years to follow, the Forest Service would even formalize its “no fire” stance through the “10 a.m. rule,” requiring the nearly impossible task of putting out every single wildfire by 10 a.m. the day after it was discovered. The rule would stay in effect for most of the century.

Yablonski pointed me to an essay called “Fire and the Forest—Theory of Light Burning” by FE Olmsted, published in the January 1911 issue of the Sierra Club Bulletin (and available via the magic of HathiTrust).  Olmsted is one of the seminal figures in American forestry, who is credited as one of the founders of the US National Forest System, and also taught forestry at Harvard. In this essay, Olmstead is writing just after the Big Burn of 1910, and he is arguing against “light burning” in favor of the fullest possible suppression of forest fires. Olmsted is find with burning an area after logging has occurred, to clean it up for new growth. But he argues that more extensive “light burning” will wipe out young trees, which is a waste of timber that could be cut in the future. He wrote:

Public discussion of the matter has brought to light, among other things, the fact that certain people still believe in the old theory of “burning over the woods” periodically in order to get rid of the litter on the ground, so that big fires which may come along later on will find no fuel to feed upon. This theory is usually accompanied by reference to the “old Indian fires” which the redman formerly set out quite methodically for purposes connected with the hunting of game. We are told that the present virgin stands of timber have lived on and flourished in spite of these Indian fires. Hence, it is said, we should follow the savage’s example of “burning up the woods” to a small extent in order that they may not be burnt up to a greater extent bye and bye. Forest fires, it is claimed, are bound to run over the mountains in spite of anything we can do. Besides, the statement is made that litter will gradually accumulate to such an extent that when a fire does start it will be impossible to control it and we shall lose all our timber. Why not choose our time in the fall or spring when the smaller refuse on the ground is dry enough to burn, the woods being damp enough to prevent any serious damage to the older trees, and burn the whole thing lightly? This theory of “light burning” is especially prevalent in California and has cropped out to a very noticeable extent since the recent destructive fires in Idaho and Montana.

The plan to use fire as a preventive of fire is absolutely good. Everything depends, however, upon how it is used. The Forest Service has used fire extensively ever since it assumed charge of the public timber lands in California. We are selling 200,000,000 feet of timber and on all the lands which we logged over we see to it that the slashings and litter upon the ground are piled up and burned. This must be accomplished, of course, in such a way that no damage results to the younger tree growth, such as seedlings, saplings, thickets and poles of the more valuable species. If we should burn without preparing the ground beforehand, most of the young trees would be killed. …

With the exception of two or three lumber companies the Forest Service is the only owner of timber in the State of California which has used and is using fire in a practical way for cleaning-up purposes. What “light burning” has been done on private lands in California, accompanied by preparation of the ground beforehand, shows that wherever the fire has actually burned, practically all young trees up to fifteen years of age have been killed absolutely, as well as a large part of those between the ages of fifteen and forty years. The operation, to be sure, has resulted in cleaning up the ground to a considerable extent and will afford fairly good protection to mature trees in case they are threatened by fire in the future. If a fire comes along it will naturally not have as much rubbish to feed upon and may not be so hot as to injure the larger tree growth. In other words, a safeguard has been provided for timber which may be turned into dollars in the immediate future. With this advantage has come the irreparable damage to young trees. It has amounted, in fact, to the almost total destruction of all wood growth up to the age of twenty years. This is not forestry; not conservation; it is simple destruction. That is the whole story in a nutshell.

The private owner of timber, whose chief concern is the protection of trees which can be turned into money immediately and who cares little or nothing about what happens to the younger stuff which is not yet marketable, may look upon the “light burning” plan as being both serviceable and highly practicable, provided the expense is reasonable. On the other hand, the Government, first of all, must keep its lands producing timber crops indefinitely, and it is wholly impossible to do this without protecting, encouraging, and bringing to maturity every bit of natural young growth. …

The accumulation of ground litter is not at all serious and the fears of future disastrous fires, as a result of this accumulation, are not well founded. Fires in the ground litter are easily controlled and put out. On the other hand, fires in brush or chaparral are very dangerous, destructive, and difficult to handle. Brush areas under and around standing timber are the worst things we have to contend with. Brush is not killed by fire; it sprouts and grows up again just as densely as before. The best way to kill brush is to shade it out by tree growth, but to do this we must let young trees grow. Fires and young trees cannot exist together. We must, therefore, attempt to keep fire out absolutely. Some day we will do this and just as effectively as the older countries have done it for the past 100 years. In the mean time we are keeping fires down in California by extinguishing them as soon as possible after they begin.

It is true that fires will always start; that we can never provide against. On the other hand, the supposition that they will always run is not well taken. If we can stop small fires at the start, fires will never run. With more men, more telephones, and more trails we shall be able to do this and at a cost of only a cent or two more an acre.

After about a century of following Olmsted’s prescription that “[w]e must, therefore, attempt to keep fire out absolutely,” and that this is possible, we are not confronted with waves of historically large wildfires. Notice that Olmsted’s reasoning for stopping all fires, may sound like a form of conservationism, is actually based implicitly on the idea that all the forests will be regularly logged!

Blocking fires changes the character of the forest. One of the other essays in the issue refers to a 2022 done by some authors at the US Forest Service, “Operational resilience in western US frequent-fire forests,” published in Forest Ecology and Management. They look at density of western US forests, and find that the policy of fire suppression has led to much more density (which I suppose Olmsted would view as a successful story of trees waiting to be logged), but also generally smaller trees as the forest growth becomes more competitive. They write:

With the increasing frequency and severity of altered disturbance regimes in dry, western U.S. forests, treatments promoting resilience have become a management objective but have been difficult to define or operationalize. Many reconstruction studies of these forests when they had active fire regimes have documented very low tree densities before the onset of fire suppression. Building on ecological theory and recent studies, we suggest that this historic forest structure promoted resilience by minimizing competition which in turn supported vigorous tree growth. To assess these historic conditions for management practices, we calculated a widely-used measure of competition, relative stand density index (SDI), for two extensive historical datasets and compared those to contemporary forest conditions. Between 1911 and 2011, tree densities on average increased by six to seven fold while average tree size was reduced by 50%. Relative SDI for historical forests was 23–28% of maximum, in the ranges considered ‘free of’ (<25%) to ‘low’ competition (25–34%). In contrast, most (82–95%) contemporary stands were in the range of ‘full competition’ (35–59%) or ‘imminent mortality’ (≥60%). Historical relative SDI values suggest that treatments for restoring forest resilience may need to be much more intensive then the current focus on fuels reduction. 

Their findings are consistent with observations on the ground. For example, Yablonski’s essay in PERC Reports mentions the views of the head of a Californian tribe, the North Fork Mono:

According to Ron Goode, tribal chairman of the North Fork Mono, prior to white settlement, Native Americans carried out “light burning” on 2 percent of the state annually. As a result, most forest types in California had about 64 trees per acre. Today, it is more common to see 300 trees per acre. This has led to a fiery harvest of destruction—bigger, longer, hotter wildfires.

Several implications follow. One is that modern forestry practices since the Big Burn of 1910 have substantially changed the character of western forests. I suppose one can argue over whether the change is on balance good or bad, but the fact of the change itself is established.

The combination of stopping burning for a century or so, along with the resulting heavy growth of trees, along with the decades-long accumulation of dead timber, along with recent years of drought conditions, have set the stage for major fires. Yablonski writes: “Fires that burn more than 100,000 acres are becoming commonplace in America. Nowhere is that more evident than in California. Throughout the 20th century, there were 45 megafires recorded in the state. In the first 20 years of this century, there have already been 35—seven in 2021 alone.”

The century-old policy of putting out every wildfire within a day of its discovery has clearly failed. The alternatives to reduce the potential fuel load for forest fires are much more widespread logging or controlled burning. Another essay in PERC Reports, by Tate Johnson, is called “Returning Fire to the Land.” Johnson describes the current situation in South Carolina:

One morning last March [2022], the South Carolina Forestry Commission website displayed the number of active fires in the state: 163. An interactive map showed each fire, represented by markers that ranged from red to orange to yellow to teal. In contrast to similar maps that are followed closely throughout the summer, particularly in the West, the markers didn’t represent wildfires. Indeed, South Carolina’s wildfire tracker showed zero active that day. Rather, these were “good” fires: prescribed burns that had been planned in advance, set deliberately, and aimed to achieve specific land management objectives, typically to control vegetation and reduce hazardous fuels.

“It’s gonna burn one day or another,” says Darryl Jones, forest protection chief of the South Carolina Forestry Commission, “so we should choose when we burn it and make sure we do it on the right days when it’s most beneficial.” He adds that the idea is to “burn an area purposely before it can burn accidentally.”

The different colors of map markers signified the purpose of each fire. Some burns aimed to improve wildlife habitat by stimulating seed production, clearing out a landscape’s lower layer of growth, or creating forest openings. Others were set to clear crop fields in preparation for planting or to burn debris piles that had been gathered and stacked. Still more were tagged “hazard reduction”: fires set to remove dangerous accumulations of pine needles, briars, shrubs, and other fuels that naturally build up in southern forests. Spring is the prime time to burn given its favorable conditions for wind, temperature, humidity, and fuel, although the burn window can extend earlier or later into the year.