Why firefighters are fighting wildfires with fire

Without fire, some plants would die out and never reproduce

The best defense is a good offense- it's a phrase used by politicians, coaches and military leaders, but some firefighters use the advice to keep the spread of wildfires under control.

From coast-to-coast, firefighters purposively set prescribed burns and backfires to rob fire of natural fuel and help some plant species survive.

Take a look at the California Department of Forestry and Fire Protection (CAL FIRE) firefighter, lobbing an incendiary device into the dry brush below. Another shoots a flare gun into the drought-ravaged grasses. These men and women sworn to fight fire are actually setting them.

"The ultimate objective of the firing operations is to starve the fire of fuel before it has a chance to reach our lines," Battalion Chief Ryan Waggoner told FOX 40 Sacramento. "If something does come out of the canyon, it has a nice buffer to slow it down and stop it."

Brush, trees and grass are considered to be fuel for wildfires that firefighters work to control through a variety of different methods, including setting the unburned brush ablaze.

For the Electra Fire in Northern California, these backfires will clear out the brush by burning it protect nearby homes. Any burning ash traveling on the wind will have nothing to ignite.


Intentionally setting a controlled or prescribed burn

Throughout the year firefighters even set prescribed or controlled burns to reduce the flammable fuel before a wildfire explodes. 


"Without it, the system gets out of balance and species will drop out, and the vegetation, and we refer to that as fuels. And the fire wood will build up and grow and grow, and eventually, it'll burn, and it'll be a catastrophic fire," Adam Peterson, Burn Boss of the Tiger Creek prescribed burn, told FOX Weather. "It's remarkable how quickly it recovers. It's going to start greening up within a week or two."

Peterson and his crew intentionally burned about 100 acres of the Tiger Creek Preserve Babson Park, Florida in July, a practice performed every three to five years. They plan to scorch more than 900 acres before the end of the month.

"It's a little intimidating… but, this is what this landscape needs to thrive," Cheryl Millet, Tiger Creek Preserve Manager said. "There are a lot of plant species, flowering plants, and they thrive with fire. But also, the fire gets rid of all the overgrowth in the shrub layer to allow them to get that sunlight."

Pyrophitic plants need flames

Some species of plants need fire to sprout seeds. Lodgepole pines and eucalyptus need the heat to melt to resin to release the seed. Other pyrophytic plants use chemicals from smoke and ash as a signal to come out of dormancy, says Britannica.com

Fire dries out green cones of the giant sequoia allowing them to crack and release seeds. Seeds in the cones can stay viable and wait for fire for 20 years, according to the California Department of Parks and Recreation. The tree can live up to 3,000 years. Bark on mature trees is also thick and fire-resistant to less intense and severe fires.

While the scene of the KNP Complex Fire in 2021 threatening the General Sherman Tree, the world's largest living sequoia, was heartbreaking, it is necessary for the species’ survival. Fire also clears out brush and smaller trees which shade would deprive the new seedling of sun and compete for water with it.


"Fire remains one important part of the lifecycle of the giant sequoia and a normal part of life in the forest," states the California State Parks website

Trees like pine and sequoias grow tall to keep their food-producing leaves far from flammable debris on the forest floor. Sequoias grow to 300 feet while ponderosa pines grow to about 150 feet tall.

The fire lily only flowers after a fire. Some botanists blowtorch their greenhouse Australian grass trees to encourage flowering, states Britannica. Wood ash is loaded with nutrients like calcium, potassium (potash), and magnesium. Carbonates in the ash also increases pH levels, making the soil more acidic, according to the University of Wisconsin-Madison Extension Office. 

Birch and aspen sprout from the burned roots and stumps, explains the Canadian Natural Resources page. 

A study by the Nature Conservancy looked at tree rings and found that southern Oregon forests burned about every eight years. Old-growth trees survived and reproduced in these less intense non-severe fires. After 1905, fires were less frequent and more severe. The conservancy wrote that European settlers arrived in the late 1800s and extinguished the regular occurring fires.


"The loss of fire has caused a gradual decline in forest health, setting our forests up for high risk of mega-fires," wrote the study’s authors. 

Prescribed burn fire risks

Every fire has its risks though. The largest fire in New Mexico’s history, the Calf Canyon/Hermits Peak fire, started when crews lost control of a prescribed burn.


"You can imagine where these prescribed burns are happening is areas where there's a lot of a lot of topography, a lot of valleys that can sort of change the wind conditions very quickly, like what happened in New Mexico," Paul Walsh, General Manager of Breezometer told FOX Weather.

Walsh said emerging technology will make controlled burns less unpredictable. 

"So what we're seeing now is a sort of evolution or revolution, I should say, in what's called climate technology, where more and more companies and governments are investing in being able to predict the weather at a very, very precise level so that we can get better and being able to, number one, identify when we should be doing the prescribed burns, but also how we should be doing and where we should be doing it so that we can make sure that we don't have an event like what happen with Hermits Peak," said Walsh.

Making the offense smarter can go a long way to the best defense.