A recent article in the Science section of the New York Times seemed to reiterate some of the common misunderstandings about wildfire. While there are parts of the article that I certainly agree with, the implicit message that large wildfires are ecologically destructive and that thinning forests will save them is highly questionable.
AFTERMATH OF LARGE SEVERE FIRE IS NOT A BIOLOGICAL DESERT
The misinformation and bias start with the very first paragraph of the article where the author says: “The repeated blazes that devastated the trees…” Using the pejorative word “devastated” to characterize natural ecological processes like wildfire shows a common bias against wildfires. But that is only the beginning of a news article that tells only part of the true ecological story.
A couple of paragraphs later, the author describes a 30,000 acre of the 2011 Las Conchas fire area in New Mexico as a “near-treeless hole” as a result of a wildfire that reburned a part of the Dome Fire. The article then quotes a research scientist who asserts that by now there would be significant regrowth of young trees.
All of this is alarmist rhetoric for a host of reasons.
First, recent reburns of earlier fires is not the usual situation in most of the West. It does happen, but it cannot be characterized as the norm. Furthermore, the time since the Las Conchas Fire is extremely short. It is not that unusual to see delayed regeneration of forests in severely burnt areas if the conditions for seedling survival are not favorable.
One must keep in mind that this area of New Mexico was suffering from one of the worst droughts in 500 years. The extended drought is one of the prime agents driving large wildfires and given that the drought is nothing like we have seen in any historic period, it is not surprising that we would be seeing wildfires unlike others that may have occurred during more favorable climatic periods.
Drought conditions also hinder pine seedling survival. This is a natural result of all plant communities. They experience “pulses” of favorable conditions and then endure the less favorable conditions. Many trees in arid environments like the Southwest establish during particularly favorable moist periods. Since they are long-lived, they endure as biological legacies even if the climate shifts to less favorable conditions.
This is not unlike what happened at alpine locations in the Cascade Range during the 1930s dust bowl years. Due to low snowfall during those years, trees were able to colonize higher elevation alpine meadow areas that normally would remain snow-covered late into the summer. Once established, and even with the return of higher snowfall years, the trees persisted. The same principle applies to lower elevation arid areas.
And while there may not be the same regeneration of pine as previously experienced during moister periods of time, this burn area is not a biological desert as implied by the message in the article. Rather there is abundant grass cover, along with some regrowth of other species like Gambel oak that sprout from their roots and thus are not reliant upon seeds to recolonize a burnt area. At higher elevations burned by the Las Cnochas Fire, there is abundant aspen resprouting. Aspen, in particular, responses well to high severity fires, and sprouting abundant in this area as a consequence of the fire. Aspen has been declining across the West because of the long absence of such fires.
In any case, a more positive way to view the Las Conchas fire is that it has revitalized and rejuvenated the area
Furthermore, no large severe fire is a biological desert as implied by the article. Even without regeneration of aspen and Gambel oak, there are plenty of snags left by the fire. Snag forests are among the rarest habitat type in the West, vastly more limited than pondoersa pine forests. Many species of wildlife and plants depend on snags and dead trees for their livelihood.
A CENTURY OF FIRE SUPPRESSION LEADING TO BIGGER MORE SEVERE FIRES IS QUESTIONABLE
The next part of the story that is an exaggeration is the assertion that a “century” of fire suppression has, according to proponents of this theory, lead to higher fuel loads and thus by natural logic is the reason for hotter, more extensive fires.
There are three problems with this common assertion that is taken as truth because it is repeated so frequently.
First, it is questionable whether we have had a “century” of successful fire suppression. In many lower elevation forests, particularly in the ponderosa pine zone featured in the article, it was livestock grazing which removed grass cover that was the fine fuels that carried fires that led to a reduction in fires, not “fire suppression.”
At higher elevations in other forest types where grass understory is less common, it is also questionable whether any “fire suppression” efforts have affected things.
Keep in mind before World War 11 the primary force for fire suppression were a few scattered forest rangers on mules and horses equipped with shovels and pulaskis riding across hundreds of millions of acres of unroaded backcountry. Can one really believe that these limited and feeble efforts significantly altered fire regimes across the West? At best one might be able to make the argument that post WW11 since the 1950s onward, fire-fighting has been somewhat effective, but this is far from a century.
Yet even today with massive armies of fire fighters, helicopters, air tankers, bulldozers, and way, way, way, more roads providing quick access to our forest we cannot control the large blazes.
But whether fire suppression has really been effective or not since the 1950s, is also questionable. In reality most plant communities have long fire-free periods. That means they do not burn even if there are ignitions from any sources—whether lightning, arsonists or an abandoned campfire.
What is not acknowledged by the “century of fire suppression” proponents is that the majority of all fires self-extinguish. For instance, in Yellowstone National Park between 1972 and 1987, there were 235 wildfires that were not attacked, rather were merely monitored and permitted to burn. All of them self-extinguished without any suppression and most burned fewer than a hundred areas. Yet under the normal scenario whereby we attack all fires, fire-fighters would have claimed that their “suppression” extinguished the blazes.
By contrast, in 1988 Yellowstone was experiencing the worse drought in its history with some of the lowest recorded humidity and high winds. Not surprisingly under these conditions, even 10,000 fire fighters with air power, bulldozers, etc. could not stop the blazes. It was snowfall on September 11th that finally put the fires to bed.
The important lesson here is that fires are largely controlled by climate/weather, not fuels. If the conditions for fire spread do not exist, it doesn’t matter how many ignitions or lightning strikes or even arsonists you have starting fires. They will not spread and/or burn significant acreage unless the climate/weather conditions are favorable.
By contrast, when conditions for a large fire exist—and these conditions are extended drought, high temperatures, low humidity and most importantly wind– you cannot stop fires. Every large fire in the West as well as in the past burns under these conditions.
MOST PLANT COMMUNITY EXPERIENCE LONG FIRE ROTATIONS OR PERIODS WITHOUT FIRES
A further problem with the “fire suppression” has led to increased fuel loads myth is that the majority of plant communities in the West do not burn very often. While ponderosa pine in some locations like the Southwest may be characterized by low intensity and frequent fires (and even this generalization about ponderosa pine has been questioned in recent years), the bulk of all plant communities do not fit this model.
Whether we are talking about chaparral in California, sagebrush in Nevada, aspen in Colorado, lodgepole pine in Yellowstone, or Douglas fir on the west slope of the Cascades, all of these plant communities and more, tend to be characterized by long fire-free periods. As a result, fire suppression could not and has not led to unnatural fuel loadings. Fuel accumulation is the natural feature of these plant communities until they burn—typically with some high severity component. .
As an example, the lodgepole pine forests that dominate Yellowstone National Park typically burn at 100-400 year intervals, and usually in large severe fires like those experienced in 1988. That is because in most years Yellowstone’s high elevation lodgepole pine forests are simply too moist to burn. As explained earlier, you can have lots of ignitions, but the fires self-extinguish. In between these large fires, fuels do accumulate—but that is the natural order of things.
Another common fallacy is thinking about fires like clocks. Even if a forest is found to burn at 100 year “intervals” that doesn’t mean that fires occur every hundred years. Like 100 year flood, you can go several hundred years without a flood, and have two 100 year floods in the same decade. Fires work the same way. You can have very long fire-free intervals, even in ecosystems where fire is relatively frequent.
I’ve even fire ecologists make the flawed argument that in these ecosystems that may burn every hundred years that 50 years of fire suppression meant that half of the area “should have burned”. Again this is a mischaracterization. If a forest burns at 100 year intervals, it does not burn half of the acreage in 50 years. Rather with the exception of perhaps some small blazes that do not burn any significant amount of the area, the bulk of the forest only burns when conditions for a large burn exist—which may be at 100 years or may be 200 years depending on the climatic conditions.
Actually most of the fires that fire fighters are “putting out” are generally fires that would not burn an appreciable amount of acreage anyway. One large wildfires will blaze across far more acreage that a thousand small 1-100 acre fires. In reality most fires do not amount to a hill of beans in terms of their ecological influence. Rather it is the occasional large fires that are responsible for doing the lion’s share of ecological work.
EVEN LARGE BLAZES ARE MIXTURE OF BURN SEVERITY
Another common misunderstanding by many people is that large fires are uniformly nothing more than “charred moonscapes”. I use those words in quotes because in reality most large blazes are a mix of burn severities and the high severity proportion is typically a small fraction of the area within the overall burn perimeter. Indeed, large blazes typically have more area unburned or lightly burned than severely burned.
LARGE BLAZES ARE NOT ABNORMAL
One of the difficult things for most people to wrap their heads around is the idea that large fires are “normal” if you have a long enough temporal and large enough spatial perspective. Our limited view of our personal time on Earth affects our ability to put these larger blazes into some kind of perspective. What you find is that even ecosystems that normally might have fairly frequent blazes, may occasionally burn more extensive areas and more severely under the right climatic/weather conditions. Just as a 500 year flood is not abnormal if you have a couple of thousand year perspective, a 500 year fire is also quite normal, even though you might have much smaller annual floods. A similar situation exists in the forest. Many small blazes may occur, but an occasional large fire will supersede and overwhelm the forest community.
EVOLUTIONARY EVIDENCE FOR LARGE BLAZES
Indeed, if one takes an evolutionary approach to fires, you will find that many plants and animals are adapted to these severe blazes, often at different points in time. In other words, immediately after a severe fire, the habitat will be ideal for mushrooms and woodpeckers. Later as the vegetation shifts to shrubs, grasses and small saplings, the habitat becomes suitable for another guild of plants and animals, and so on all the way until there is mature forest.
And many species even though dependent on the mature old growth forest still rely on the occasional large severe blazes to create important habitat. For instance, the spotted owl which roosts and nests in old growth forest habitat still forages in burns. Fires create an abundance of rodents that invade burnt areas to take advantage of all the grass and flower seeds that occur immediately after a burn.
CARBON LOSSES DUE TO FIRES QUESTIONED
Another theme of the article is that as forests burn and are replaced by shrubs or grasses, we will be losing carbon that might otherwise be sequestered. There are several problems with this assertion which on its face may seem self-evident-fewer live trees means less carbon storage. The first, is that even a burned forest retains a lot of its carbon in the form of snags and roots in the ground. What burns in a fire is the fine fuels like needles. This does represent a loss of carbon, but it’s small compared to what remains on site as dead wood.
Furthermore, it’s not clear that on global scale a loss of carbon sequestration in arid areas like New Mexico isn’t balanced out by greater growth in other regions of the Earth. Arid environments do not store or sequester as much carbon as plant communities in moister more benign areas of the Earth. Rising CO2 levels tend to increase plant growth, and in places not limited by moisture, this additional growth may more than balance out for a loss of forest cover in someplace like New Mexico—if there is actually a long term shift in the first place.
THINNING FORESTS DOESN’T WORK
Another fallacy in the article is the implication that if we only thinned enough forests, thus reduce fuels, we could prevent large fires. Again this fails to understand that climate/weather is what largely drives our larger wildfires. There have been many review articles as well as anecdotal examples from around the West demonstrating that fuel reductions, particularly tree thinning generally does not preclude large blazes under severe fire weather conditions.
Whether due to natural climatic variation and/or due to climate change, we are experiencing more extreme weather than in the recent past. These conditions are pushing the large fire events we are seeing. In particular, wind-driven fires are nearly impossible to contain or control. Burning embers blown miles ahead of any fire front, and fire line starts new blazes. Under ordinary circumstances until the weather changes, fire-fighters cannot contain a fire.
FUEL REDUCTION EFFECTIVENESS QUESTIONED
In fact, thinning can exacerbate fire spread because it often puts more fine fuels on the ground, and opens the forest stands to greater drying and wind penetration. Under ‘moderate” weather conditions, fuel reductions might appear to work, but they fail completely when there are severe fire conditions.
At least on many public lands across the West, fuel reductions are not necessarily done correctly to be most effective. That is due to many limitations. Many fuel reductions are merely timber sales in disguise, so and not removing the small fine fuels, they often also take out the more fire resistant larger trees.
And even where there is mechanical thinning, research has demonstrated that following with prescribed fire greatly enhances the effectiveness. However, for a host of reasons, including the limited window for safe prescribed burning as well as social concerns about smoke, most fuel reductions are not followed by prescribed burning.
Even if it could be proven that fuel reductions were effective, there are limits imposed by other factors. First, fuel reductions by reducing competition for water and light tend to grow new plants rapidly. So their effectiveness declines rapidly over time. Unless they are continuously maintained, you can’t rely on them to slow fires. As a result most fuel reductions will not encounter a fire during the period when they might actually work.
FIRES AND BEETLES ARE NATURAL THINNING AGENTS
Another problem with the article is that it reinforces the failed ecological notion the idea that somehow beetles and fires are a problem for plant communities and indicative of an “unhealthy” forests. In reality these agents are what maintains healthy forest ecosystems.
Beetles and fires are better selective agents at picking which trees are better adapted to the changing climate/weather conditions than any forester with a tree marking paint gun or logger with a chain saw. In the long run if climate/weather conditions make a site unsuitable for any particular tree, you will not have trees there whether thinned or not, especially if there is no immediate change in climate conditions.
These natural agents are like wolves are to an elk herd. They thin elk numbers to be in better balance with food supplies. But many studies have shown that wolves pick the less fit animals—unlike human hunters which tend to select the fit individuals.
The mindset of most foresters is like that of Fish and Game departments and hunters who tend to see wolves as harmful to “healthy’ elk herds, when in fact, it is the wolves that are creating and sustaining healthy prey populations.
Similarly wildfire and beetles are the “wolves” of the forest that helps to maintain healthy forest ecosystems.
CLIMATE CHANGE MESSAGE IS IMPORTANT
The important message of the article is that climate change is likely to change or already has changed the plant communities we have come to know. Certainly that is likely. The solution is to reduce the factors contributing to climate change, which most immediately is to halt the burning of fossil fuels, as well as meeting a more long-term reduction in human population and consumption.
If we do not make this shift, than the loss of forest at least in more the more arid parts of the West forecast by the article will almost certainly come to past. But the solution isn’t more logging and forest manipulation. We should accept the natural pruning that is occurring and learn to manage ourselves, not the forest.