Prescribed fires provide ecological benefits to forest health

Prescribed fires provide ecological benefits to forest health
Underburning allows land managers to return low intensity fire to the landscape, which mimics natural fire and provides important benefits to forest health. Photo credit: Eldorado National Forest.

Submitted by Lisa Herron, USDA Forest Service

Tahoe Fire & Fuels Team (TFFT) partners regularly conduct forest thinning (fuels reduction) projects at Lake Tahoe to reduce excess vegetation (fuels) that can feed unwanted wildfires. But did you know that fire is a natural process in the Sierra Nevada that provides ecological benefits that cannot be duplicated by fuels reduction projects alone?

Prescribed fire is an important tool used by land managers that not only helps reduce the buildup of fuels, it also allows them to reintroduce fire back onto the landscape, which is essential to forest health and resilience.

Before modern wildfire suppression efforts became common practice, low to medium intensity natural (lightning caused) fires routinely burned in the forests of the Sierra Nevada. These natural fires burned mainly on forest floors removing small trees, dense brush and forest litter, but allowed mature trees to survive the flames. This natural process not only reduced surface fuels, it helped the remaining trees increase their resistance to insects and disease by reducing competition for sunlight, nutrients and water, leading to a healthier forest over time.

Land managers use different methods to reintroduce low intensity fire back onto forested landscapes including pile burning and understory burning.

Pile burning is intended to remove excess fuels (branches, limbs and stumps) that can feed unwanted wildfires and involves burning slash piles that are constructed by hand and mechanical equipment. Depending on the conditions, fire can creep around on the forest floor between piles and provide some ecological benefits.

Understory burning is low intensity fire that takes place on the ground (the understory) and uses a controlled application of fire under specific environmental conditions that allows fire to be confined to a predetermined area. Understory burning is more beneficial than pile burning because it mimics natural fire and provides important benefits to forest health that are required to attain resource management objectives and includes controlling fuel buildup on forest floors, rejuvenating vegetation and restoring ecosystems that benefit from natural fire.

Low intensity fire also removes low-growing underbrush, clears the forest floor of debris and opens it up to sunlight and nourishes the soil. Reducing competition for nutrients allows established trees to grow larger, stronger and healthier. History teaches us that hundreds of years ago forests had fewer, healthier trees.

Smoky skies in the Great Basin. Image: Bob Conrad.
Prescribed burning can be a means of protecting air quality by mitigating the occurrence of large wildfires and the smoke that accompanies them. Image: Bob Conrad / Nevada State News

Forests today may have more trees than in the past, but they are not as large or healthy. Established trees have to compete with undergrowth for nutrients and space. Fire clears the weaker trees and debris and returns health to the forest. Clearing brush from the forest floor with low intensity flames also helps prevent large wildfires that spread out of control and completely destroy forests.

Low intensity fire is an agent of renewal in these fire-prone environments. Even smoke can be essential to survival for species like salmon or the Pacific giant salamander, as it can cast shade and cool water temperatures during warm weather. Lake Tahoe is home to many great creatures and wildlife need fire-scarred trees for habitat just as much as they need the freshly sprouted foods that fire provides.

When wildfires start in healthy, thinned forests the result is a low intensity fire that remains on the ground burning grasses and vegetation, but causing little damage to trees, which in turn allows for easier control.

Prescribed burning can also be a means of protecting air quality by mitigating the occurrence of large wildfires. Basic Smoke Management Practices (BSMPs) applied on prescribed burns can mitigate the impacts of smoke to public health, public safety and nuisance, and visibility. Unlike an unplanned ignition, prescribed fires are started under specific conditions outlined in a prescribed fire burn plan.

As you travel around Lake Tahoe, you may see smoke in the air from prescribed fire operations or see piles that are curing for a future prescribed burn. Please show your support for the fire and fuels management programs that are taking place around the lake. Each acre treated for fuels management is one less acre susceptible to catastrophic wildfire.

The Tahoe Fire and Fuels Team (TFFT) consists of representatives of Tahoe Basin fire agencies, CAL FIRE, Nevada Division of Forestry and related state agencies, University of California and Nevada Cooperative Extensions, the Tahoe Regional Planning Agency, the USDA Forest Service, conservation districts from both states, the California Tahoe Conservancy and the Lahontan Regional Water Quality Control Board. Our Mission is to protect lives, property and the environment within the Lake Tahoe Basin from wildfire by implementing prioritized fuels reduction projects and engaging the public in becoming a Fire Adapted Community.