Controlled Burns: Pros and Cons

The middle of a forest fire
Prescribed burn in long-leaf pine forest. PetePattavina / Getty Images

Wildfires are a natural part of many healthy ecosystems. However, the difficulty of managing wildfires, especially around people, led to decades of fire suppression by the U.S. Forest Service and other agencies during the 20th century. Today, scientists understand the need for regular fires for both ecosystem management and human safety. 

To balance the risks and benefits of fires, federal and environmental agencies conduct prescribed or controlled burns — fires that are meticulously planned, intentionally set, and carefully managed.

Prescribed burns can mimic natural fires while allowing land managers to determine exactly when and where an area will burn. However, controlled fires also entail some of the downsides of any fire. Burning large areas releases smoke and particulates that can damage air quality. And, no matter how well planned, is never without some risk of getting out of control.

Benefits of Controlled Burns

Fire is essential to the health of fire-adapted ecosystems. Controlled burns can mimic natural fires, bringing with them ecological and social benefits. Regular burning also reduces fuel loads and prevents more catastrophic wildfires that can harm people and property. 

1. Lower Risk of More Dangerous Fires

The risk of wildfire is always present in many ecosystems. However, controlled burns can help minimize that risk by reducing fuel loads and by establishing a timeline of burns. Using prescribed fires as preventive management can save lives and billions in property damage.  

2. Native Plant Reproduction

Sunlight on Yellow Wildflowers in Burnt Forest Hillside
Native plants emerge after a forest fire. Created by MaryAnne Nelson / Getty Images

It may seem counterintuitive that fire can be good for plants, but that is the case for species evolved to cope with fire on a regular basis. Many pine tree species, like lodgepole and jack pines, have serotinous cones that require heat to release the seeds. Other species, like the longleaf pine, produce seeds that need the bare mineral soil left after a fire to begin germinating. Without fires, populations of these species can dramatically decrease and have cascading effects on the ecosystem. 

3. Control of Invasive Species 

Controlled burns can also help native vegetation by curbing invasive species. When fire is absent from an ecosystem, fire-intolerant plants have the opportunity to take root. Prescribed fires help native plants compete and even thrive, thus providing a habitat for native animals. 

4. Habitat for Wildlife 

High Angle View Of Gopher Tortoise On Field
Gopher tortoise on field. Heather Mahaffey / EyeEm / Getty Images

Some animals need the open habitat created by fires to feed and reproduce. In grasslands, animals like quail nest in grassy habitats created by regular fires. Other species, like the endangered gopher tortoise, are declining due to fire suppression in their native ecosystems. Regular fires make it easier for gopher tortoises to dig their burrows and also create openings where they can bask in the sun.

5. Minimize the Spread of Pests and Diseases

Prescribed fires can help control pest and disease outbreaks in forests. When certain tree species are infected, they experience delayed growth for some time before they die. This gives the pest or disease a chance to spread to trees in the surrounding area. These smaller, diseased trees, however, have not developed fire-resistant bark, which allows the prescribed fire to clear the unhealthy trees and protect the rest of the forest.

6. Improve Watershed Conditions

Controlled burns benefit watersheds by preventing more intense and damaging fires. According to the Environmental Protection Agency (EPA), when a fire burns too hot it can cause erosion and allow excess nutrients and sediment to get into the water. Prescribed fires can have some of these detrimental effects as well, but they tend to be minimal and short-lived, so they're not as harmful. Fire can also decrease plant demand for water in an area, which allows more of the precious liquid to remain in streams.

7. Reduce Tree Competition

Prescribed fires can make individual trees healthier by reducing competition with other trees and plants. This is particularly important when growing trees for timber. With fewer plants competing for nutrients, water, and space, valuable trees are likely to be healthier and grow larger.

The Potential Downsides of Controlled Burns

A firefighter conducting a controlled burn with a drip torch
Cavan Images / Getty Images

Controlled burns carry many ecological benefits. However, there are downsides to igniting an ecosystem, mostly due to the sometimes unpredictable nature of fire. Many of these drawbacks, like lower air quality, are short-term and would be worse in the case of an uncontrolled wildfire.

1. There’s Always Some Risk

Even the best-laid plans sometimes go awry — especially when dealing with fire. For example, weather conditions can shift quickly and unexpectedly, causing fires to burn outside of the planned perimeter. In these cases, controlled burns carry similar risks to wildfires in that they can threaten people’s lives and property. For example, an extreme case occurred in 2012, when a burn prescribed by the Colorado State Forest Service led to three deaths and 23 houses destroyed. A poorly handled controlled burn can sway public opinion against fires for ecosystem management, which can have long-term effects.

2. Air Quality

The smoke and particulates released during controlled burns can negatively affect air quality. Inhaling these substances is dangerous for human health and can cause short- and long-term respiratory problems including asthma, chronic obstructive pulmonary disease (COPD), bronchitis, and pneumonia. To mitigate the effects of controlled burns on air quality, managers can try to burn on days when the wind will clear smoke more quickly.

3. Water Quality

Any forest fire, whether planned or unplanned, can affect water quality. Prescribed burns can lead to some soil erosion, adding sediments and excess nutrients to streams. To avoid these effects, land managers will leave riparian zones — the areas immediately adjacent to streams — unburned.