Myths of Prescribed Fire: The Watering Can that Pretends to be a River

Prescribed fire, which isn't the same as cultural burning, is inefficient for public safety and ecological restoration.

The use of prescribed fire — intentionally setting fires in forests and other ecosystems under planned circumstances — has received increased attention in California and elsewhere in recent years. On the one hand, it is good that there is growing recognition that fire is a natural and necessary part of forests and other ecosystems. On the other hand, current advocacy for large-scale prescribed fire across vast areas is often built on outdated assumptions and overstated claims, while downplaying problems stemming from how prescribed fire is actually being implemented. This factsheet identifies five key sets of myths regarding prescribed fire and shows how they can lead to misguided policies and missed opportunities to better accomplish public safety and ecological restoration goals in a more cost-effective manner. To create effective fire policies, we need to face these facts — Prescribed fire increases fire and smoke. Prescribed fire is inefficient for public safety compared to home retrofits. Prescribed fire is inefficient for ecological restoration compared to managed wildfire. Prescribed fire can be harmful. And prescribed fire and cultural burning are not the same.

Current advocacy for large-scale prescribed fire across vast areas is often built on outdated assumptions and overstated claims, while downplaying problems stemming from how prescribed fire is actually being implemented. Photo by CALFIRE.

Prescribed Fire Increases Fire and Smoke

A central myth is that increasing prescribed fire will lead to less fire and smoke overall. Proponents of prescribed fire highlight examples where a portion of a wildfire halted when it encountered a previously burned area, but these anecdotes are the exception rather than the rule. The reality is that wildfires can burn through previously burned areas as soon as eight months after the prior fire. Over 106,000 acres within the 2020 LNU Lightning Complex in California had burned within the previous five years, with 67,000 acres having burned just two years prior. As fire researchers have stated, “fuel treatments are not intended to stop wildfires.” Instead, the main goal of prescribed fire is to somewhat alter subsequent fire intensity in the affected area, though that may not occur under unfavorable weather conditions. In other words, prescribed fire is additive to, rather than being a substitute for, wildfire. Even in instances where prescribed fire has been found to limit wildfire extent, the acreage of a prescribed burn significantly exceeds the acreage of subsequent wildfire reduction, with 3 to 4 units of prescribed fire needed to reduce wildfire by one unit. Furthermore, the effects of prescribed fire on wildfire behavior fade within a few years. Within as little as 2 or 3 years after prescribed fire, combustible understory vegetation can return to levels equal to or greater than levels prior to prescribed burning. Thus, prescribed fires would need to be reapplied on a regular basis, repeatedly adding fire to many places that otherwise might not encounter a wildfire until many years in the future. For all these reasons, increased use of prescribed fire will likely lead to a net increase in the total amount of fire.

With that additional fire comes additional smoke. Proposals to implement landscape-wide prescribed fire could result in ten times as much smoke. In addition to increasing the total amount of smoke, increasing prescribed fire also increases the duration of smoke exposure. While wildfire smoke is concentrated in the height of fire season — and landscape-scale use of prescribed fire would not preclude this — prescribed fires are typically lit in the “shoulder seasons” when wildfires are less likely, and thus prescribed fires prolong smoke exposure into times when it would not otherwise occur. There can be circumstances where it is appropriate to use prescribed fire, but it should be done knowing that the effect will be an overall increase in the amount and duration of fire and smoke.

Prescribed Fire Is Inefficient for Public Safety Compared to Home Retrofits

Prescribed fire is an inefficient and relatively ineffective way to protect homes and communities during wildfires. As Dr. David Lindemayer recently summarized, “The peer-reviewed evidence is that burning forest miles from houses doesn’t protect those houses.” As discussed above, prescribed fires generally do not stop subsequent wildfires, and altering fire intensity is largely irrelevant to community safety because home ignitions during wildfires are rarely caused by direct contact with high-intensity fire. Instead, home fire-safety retrofits (“home hardening”) offer the most effective ways to keep communities safe during wildfire. Yet the resources to help communities with fire-safety retrofits are currently quite limited compared to the government funding for prescribed fire and associated “fuel treatments” in wildlands. For example, in California’s 2021 proposed budget for wildfire preparedness, less than 4 percent of the funding is directed to “community hardening.” While prescribed burning adjacent to communities can potentially have some benefits, proposals to use large-scale prescribed fire across vast landscapes away from communities represent a remarkably indirect and inefficient way to protect houses when compared with the direct benefits of home retrofits.

Prescribed Fire Is Inefficient for Ecological Restoration Compared to Managed Wildfire

One positive outcome of the greater attention on prescribed fire is that it has contributed to growing recognition that fire is a necessary part of forests and other ecosystems, and that currently many forests have a shortage of fire compared to levels prior to modern fire suppression. Unfortunately, many advocates for prescribed fire rely on an outdated “good fire/bad fire” dichotomy that is out of step with the science. In this false dichotomy, prescribed fires are characterized as “good” because they are associated with low-intensity fire, whereas wildfires are characterized as “bad” because they are associated with mixed-intensity fire that includes some areas of high-intensity fire. However, there is a growing body of research showing that high-intensity fire has always been a part of forests and other ecosystems, and it produces ecological benefits by creating excellent wildlife habitat and stimulating nutrient cycling. In contrast, low-intensity fire associated with prescribed burning does not generate the habitat creation and the nutrient cycling associated with higher-intensity fire. Each type of fire intensity has its role in a mixed-intensity fire regime, and low-intensity fire is not a substitute for the benefits from some higher-intensity effects in forests.

Another myth repeated by some prescribed advocates is the erroneous notion that forests that previously experienced fire suppression will now “burn up” in all or mainly high-intensity fire when a wildfire occurs, unless those forests first get prescribed fire or other “fuel treatments.” But multiple studies have shown that areas that experience wildfire following long periods of fire suppression still burn mainly at low and moderate intensity, along with some high-intensity patches that provide the benefits described above (see here and here). In fact, research has found that forests with the longest fire exclusion actually burn at somewhat lower intensity. This is exciting news for efforts at ecological restoration because it means that large-scale prescribed fire or other “treatments” are not needed as a precondition to allowing mixed-intensity wildfire back into forests.

Instead, managed wildfire offers a much more efficient way to restore fire to forests that currently have a shortage of fire, and this has economic and practical benefits. Managed wildfire (also known as wildland fire use) differs from fire suppression in that, rather than trying only to extinguish a wildfire, fire managers seek to shepherd the fire away from communities and into wildland areas where the fire will provide ecological benefits. This is less intensive and costly than full suppression. Likewise, managed wildfire differs from prescribed fire because the latter has an extensive planning process and often quite restrictive parameters before a prescribed fire ignition can occur, whereas managed wildfire works with natural fire ignitions to provide more fire where it is needed in a more expeditious manner.

This is not to say that prescribed fire does not have a role in fire policy, but instead that role has been overstated. Prescribed fire is a useful tool when there are special circumstances where fine-scale control over fire is needed. In this regard, prescribed fire has a role equivalent to the role of a watering can. A watering can is a good tool for tending the plants around your house, but if you are faced with a dry field in need of irrigation, it would be absurd to propose buying thousands of watering cans. Yet this is basically equivalent to current proposals relying mainly on prescribed fire to restore fire to vast areas. Instead, the right way to water a large field is through large-scale irrigation — a river, not a watering can — and the most efficient way to restore fire to large landscapes is through managed wildfire. Yet, despite its benefits, managed wildfire currently gets surprisingly little attention in current fire policy discussions, compared to prescribed fire.

Prescribed Fire Can be Harmful

Prescribed fire is sometimes called “good fire” by its proponents, but the reality is that, while it can be useful in some circumstances, prescribed fire can also cause ecological damage. One example is when prescribed fire policies get applied to non-forest ecosystems such as chaparral, Great Basin sagebrush, or pinyon-juniper woodlands. Research over the past few decades has established that these ecosystems naturally and historically burned infrequently, with several decades or even centuries between fires (see here, here, and here). In these ecosystems, the use of prescribed fire can shorten fire-free intervals needed for slow-growing shrubs to re-establish, and such fire conducted outside of the natural fire season can inhibit seed germination for many species while favoring growth of non-native plants that can be more flammable (see here, here, and here).

Prescribed fire can also be harmful in forests, especially when done outside of the main fire season. Wildlife have evolved strategies to coexist with summer forest fires, but prescribed fires are often lit in the spring when bird eggs and nesting chicks cannot get away from fires. There can also be significant ecological damage when logging (“thinning”) is treated as a prerequisite for prescribed fire. On national forests, this means that Forest Service projects involving prescribed fire can also include substantial amounts of logging that damages wildlife habitat. Furthermore, logging results in cut vegetation debris that then gets piled up and burned. The Forest Service is now calling this pile burning “prescribed fire,” but it causes sustained burning in a concentrated location that can scorch and sterilize the soil, and it does not produce the beneficial post-fire wildlife habitat created during genuine forest fire restoration. In light of these potential harms, projects involving prescribed fire should not be exempted from proper environmental review.

​The Forest Service is now calling pile burning ‘prescribed fire,’ but this concentrated burning can sterilize the soil. Photo by NPS / M.Quinn.

Prescribed Fire and Cultural Burning Are Not the Same

As attention on prescribed fire has grown in recent years, there has also been broader awareness that Native Americans have long traditions of applying fire to the land in practices known as cultural burning. Cultural burning was outlawed or severely restricted when federal and state policymakers imposed their wildfire suppression policies on Indigenous peoples. Now some Indigenous groups seek to restore their ability to do more cultural burning. Traditionally, burning has been done for a variety of purposes, including stimulating the growth of plants that are particularly useful to their communities, such as for basket-weaving or food production. In this regard, traditional cultural burning is notably different from current approaches to prescribed fire from the Forest Service and other agencies that primarily focus on trying to suppress forest fire intensity across vast areas. Yet, the Forest Service’s approach to prescribed fire often gets conflated with traditional cultural burning in discussions of fire policy. This can result in cultural appropriation that superimposes Forest Service goals on Tribal practices. The evidence is clear that, prior to modern fire suppression policies, Native American cultural burning and mixed-intensity forest fires were both much more common than they are now ( see here, here, and here). They coexisted, and one did not preclude the other. Both have been suppressed and marginalized by federal and state agencies.

Conclusion — The Disappointing Results of Prescribed Fire

When all is said and done, the actual results from broad-scale application of prescribed fire would likely be disappointing for most people. Those who thought it would reduce fire would instead experience more fire and smoke from large-scale prescribed burning. Those who are concerned about public safety would realize that communities would have been much safer if the money used to subsidize backcountry prescribed fires and associated “fuel treatments” had instead been focused on directly assisting with fire-safety home retrofits as part of a home-outward strategy. Those who want to help ecosystems would realize that managed wildfire offers a more efficient and practical way to restore fire to forests, whereas prescribed fire is often tied to increased logging. And those who want to support Tribes’ cultural burning would find traditional practices getting appropriated by federal and state agencies. While prescribed fire can have some benefits in special circumstances, it is important to not overstate the role of prescribed fire — a watering can should not pretend to be a river — or we risk missing more effective and cost-efficient solutions using managed wildfire, traditional cultural burning, and home fire-safety retrofits.

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