What happens when someone deliberately sets a fire outdoors? Igniting a grass or brush fire usually results in an arson charge, so why do state park staffers light them?
California State Parks foresters and environmental scientists use controlled fire to restore plant and animal habitats and to reduce the chances of large, destructive wildfires. These treatments, called prescribed burns, are managed under close supervision within a predetermined area.
Until the 1960s, fire and land management agencies believed that all wildland fires, whether caused by lightning or by humans, should be extinguished as quickly as possible. However, lengthy droughts in the 1970s and 1980s dried out more living trees in our wildlands, increasing their susceptibility to insect invasion and death. As the biomass (volume of living and dead trees, grasses, brush and debris) increased, the severity of wildfires increased proportionally.
After years of fire suppression, many areas of California that had experienced wildfires regularly for thousands of years had not burned for decades. These wildlands were then covered with unnaturally high levels of trees, shrubs and dead debris. Under these conditions, a lightning bolt, an equipment spark, or a careless person’s match, cigarette or campfire can create a large, destructive wildfire.
In addition to creating higher fuel loads in some areas, fire-suppression activities during the last century have altered many native plant and animal communities. Most of California’s native plants and animals have lived with and adapted to fires for thousands of years; they are even nurtured and sustained by periodic fires.
For example, lizards will go underground and slow their respiration rate to avoid scorching and suffocation by fire; giant sequoia cones will open to disperse new seeds only after exposure to extreme heat. Most species have adapted to periodic wildfire to ensure their survival or that of their offspring.
The importance of strategic fire in maintaining the health of natural ecosystems and reducing the frequency of catastrophic wildfires is now better understood. The first park prescribed burn took place in 1973 at Montaña de Oro State Park. The Department’s prescribed burn program began in earnest with multiple burns in the giant sequoia groves at Calaveras Big Trees State Park during the late 1970s. Formal staff training in fire ecology, prescribed burning and fire management began in 1981.
Grassland management at Point Lobos State Natural Reserve
Forest understory burn at McArthur-Burney Falls Memorial State Park
Reforestation preparation at Cuyamaca Rancho State Park after wildfire
Several hundred prescribed fires in more than 40 park units have been planned and executed since the program’s inception. Some are managed wholly by park staff, while other burns are planned with state, federal, or local firefighters.
Fire managers consider many factors when planning prescribed burns. Key elements include the area’s natural fire cycle and the existing conditions of native plants and animals. Prescribed burn timing is based on conditions of air temperatures, humidity, wind patterns, terrain, and moisture levels of both live and dead plants. If fire is needed for invasive plant elimination, the plant’s physiological stage is also factored.
Prescribed burning restores the role of natural fires that periodically clear the landscape. Although recently burned areas may look barren or damaged, many native plants quickly recover from fires, especially after the first rains. Burning helps release nutrients in the soil and stimulates seed germination and plant growth. Controlled burns can help manage non-native plants that compete with and displace native species.
Brush control at Humboldt Redwoods State Park
Prescribed burns in our state parks help protect and restore important natural areas for the enjoyment of present and future generations of park visitors.