Prescribed Fire

California’s Fire-Adapted Landscapes

Many of California’s landscapes are fire-adapted, which means trees and vegetation that experience frequent fires are resilient to or dependent on fire. Here in Sonoma County, oak woodlands, redwoods and grasslands evolved with fires set by Indigenous Peoples as a way of maintaining healthy and vibrant ecosystems over thousands of years. As a result, native trees and plants possess qualities like thick bark and fire-stimulated flowering, seed release and germination.

When the first European explorers encountered these landscapes, they reportedly marveled at their picturesque, park-like qualities which were a result of management by Indigenous Peoples over thousands of years. Intentional fire cleared dead and downed woody material, released nutrients into the soil and initiated new plant growth on which the animals and people depended.

Current Conditions

As Sonoma County was settled, wildfires were frequently suppressed. This led to the buildup of large amounts of fuels, which refers to anything that can burn and spread fire like trees, shrubs and dried grass. In addition, logging often removed the largest trees and caused regenerating forests to grow into dense, impenetrable stands of vegetation fighting for limited resources. These conditions, along with invasive pathogens like sudden oak death and drought-related bark beetle outbreaks, created highly combustible forests. 

Climate change has also increased fire intensity and severity by raising daily temperatures and lengthening the annual dry season. As a result, we now regularly experience catastrophic wildfires in California.

Solutions

But there are solutions that can nurture our landscapes back to health. However, it will take time and a commitment to work with the ecological processes that have shaped these landscapes for eons to accomplish this. 

Wildfire behavior is determined by three factors: fuels, weather and topography, but only fuels are controllable. Sonoma County Regional Parks uses the following tools to transform young, dense forests and woodlands into mature, self-sustaining ecosystems reminiscent of the past and resilient to the conditions of tomorrow:

Grazing 

Grazing is a cost-effective way to reduce grasses and shrubs. It is the first step in a multi-tool process to help reduce future wildfires. Grazing mimics the natural disturbance of the landscape by large animals like bison and elk that used to roam Sonoma County and, when carefully managed, can help support habitat for native plants and animals. This practice also sequesters carbon and recharges groundwater.

Learn more about grazing in our parks

Vegetation management

Ongoing seasonal vegetation and fuels management projects include ecologically appropriate tree and brush thinning and removal, sometimes referred to as a shaded fuel break. Unlike a fire break, where all vegetation is removed, a shaded fuel break retains larger trees to provide shade and wildlife habitat. Shaded fuel breaks have been shown to effectively decrease wildfire severity even during extreme situations. They can also be excellent control (or boundary) lines during prescribed fire operations. Natural Resources staff also use targeted mowing and road clearing to improve emergency vehicle access.

Prescribed fire

Prescribed fire is a vital element that has been missing from our landscapes for over 100 years. Prescribed fire (also known as a controlled burn) is the purposeful use of fire in an area. It is carefully planned and carried out under specific weather and fuel moisture conditions called a “prescription.”

Goals for prescribed fire are to:

• restore ecosystem health
• reduce invasive species or built-up vegetation, including “ladder fuels” which enable fire to climb into the tree canopy
• reduce wildfire risk
• train fire personnel

Different types of prescribed fire include:

• Broadcast burns which intentionally apply low-intensity fire across a large, predetermined area of land, mimicking natural fire patterns as much as possible.
• Pile burning, which is the intentional burning of concentrated piles of collected vegetation or “slash” from thinning wooded areas.
• Burning with a “curtain burner,” also known as a “trench burner” or “air curtain incinerator,” that uses a powerful fan to blow a high-speed curtain of air across a fire, trapping smoke and sparks and creating a clean-burning, efficient combustion of wood and brush.

Even with the use of prescribed fire, future wildfires will occur, but they will be lower-intensity fires that don’t burn entire forests. This kind of fire can also help initiate ecosystem processes that are encouraged by fire such as nutrient cycling, seed dispersal, germination, reduction of pathogens and protection of mature trees that will continue to sequester carbon. All of this, ultimately, helps protect parks and adjacent communities, making them more resilient to wildfires and climate change.

More information

If you'd like to learn more about the use of prescribed fire in our parks, visit the links below:

• Sonoma County Resilient Forests and Watersheds Initiative
• Prescribed Fire: Community Based Burning in California (Video)
• Pile Burning in Sonoma County (Video)
• For tribes, 'good fire' a key to restoring nature and people (Press Democrat)
• Wildfire and Prescribed Burn Emissions (California Air Resources Board)
• Watch Duty - wildfire maps and alerts
• Good Fire Alliance