A century of firefighting is making wildfires worse and damaging forests

As parts of the country are usually not affected by wildfires shrouded in smoke In recent months, experts are turning to a centuries-old practice as a way to cope more and more severe Forest fires.

According to experts, the cause of the problem lies in the long-standing policy of fire exclusion: keeping fire out of the forest.

For almost a century starting in the late 18th century, firefighting was America’s national policy, putting out fires as soon as they started. While this has been successful in reducing the amount of forest fires, over time it has resulted in a build up of highly flammable dead trees and scrub on the forest floor.

Sean Parks, Ph.D., is a research ecologist at the United States Forest Service Fire Sciences Lab in Missoula, Montana, where he studies how fire behaves in forests. He says debris, also called fuel, leads to larger, hotter fires.

“Now the fires we’re seeing are killing all or most of the trees,” Parks said.

CBS News traveled to Montana as part of our “On the Dot” program. climate reportingto learn why fires burn so much hotter and the impact becomes so much greater.

That was not always so.

In Montana’s Bitterroot National Forest, parks lead us to fire-scarred trees. By cutting a cross-section from a tree stump, Parks shows that trees can bear scars from long-ago fires, set every 10 to 30 years by the Bitterroot Salish tribe who lived here.

And yet these trees survived. You can see curls in the wood showing where the tree was scarred and started to regrow around that scar.

Research shows that these scars are evidence that Native Americans have successfully controlled wildfires by regularly starting smaller fires to reduce fuel build-up.

After the US drove the tribe off the land and began the practice of foreclosure fires in the forest, many trees did not experience fire for a century or more.

In fact, the tree does not bear any burn scars for 100 years during the fire fighting policy. All around, fuel accumulated unabated during those years, fueling future fires that burn hotter and deadlier today, Parks says.

Those worse fires ultimately killed this centuries-old tree, Parks said.

“Many of these forests are no longer well prepared to survive this inevitable fire,” Parks said.

Parks says climate change is making this problem worse.

“There’s definitely a link between more fires and climate change,” Parks said. “Due to climate change, fuels are now drier. And when fuels are drier, fires burn hotter and are also harder to put out.”

Start good fire to prevent bad fire

The Confederate Salish and Kootenai tribes of Montana are leading the way in bringing prescribed fire back to the landscape.

“It reduces the fuel pollution that is present here that would not be here naturally,” said Darrell Clairmont, who is responsible for managing fuel pollution in the reserve’s forests.

To kindle such a fire, ideal conditions are required: moderate humidity, low temperature and little wind.

In June, the Confederate Salish and Kootenai Tribes made the final preparations for conducting a mandatory burn and invited us to join them. However, the fire had to be stopped after an unexpected rainstorm.

According to Clairmont, it is becoming increasingly difficult to achieve ideal combustion conditions.

“We’re used to burning a few thousand acres a year, and this year we probably did maybe 300 acres,” he said.

Shrinking fire windows are a problem. A study by the International Journal of Wildland Fire looking at the US Southeast found that “even meeting basic fire criteria (as defined today) becomes increasingly difficult over time” as the climate changes.

In California, for example, the state wants to burn one million hectares of land annually by 2025. But last year only 110,000 hectares were burned.

See the effects of fire on the forest

CBS News also followed research ecologist Kim Davis of the Fire Lab in Montana to see badly burned areas and understand why some forests recover from fires while others struggle.

23 years ago, the Valley Complex Fire devastated Montana’s Bitterroot Forest at Rye Creek. Traces of the destruction can still be seen today: dead tree trunks are scattered on the slopes. There is little sign of recovery. Davis says that’s because when all the trees are eradicated, there are no seeds left to regenerate.

“Where we’re standing right now, it’s really a long way from any live trees that survived the fire,” Davis said.

Much of this area has been replanted with seedlings, but many of those seedlings are dying.

Davis says that unlike mature trees, which can cope with warmer and drier conditions, today’s climate makes it harder for seedlings to establish themselves in areas that are warmer than they were 50 years ago.

“If you look at some of these areas, it becomes pretty clear that we’re definitely already seeing changes due to climate change,” Davis said.

An analysis by the US Forest Service estimates that 4 million hectares of forest – about the size of Connecticut – may need to be reforested.

But there are also bright spots.

Nearby, Davis points out another section of forest that is recovering. This is a place where the Valley Complex Fire got through but burned less severely. As a result, some old trees were preserved. Now they donate seeds and shade, allowing the seedlings to regenerate successfully.

According to Davis, protecting old trees from the effects of extreme fires plays a critical role in promoting forest recovery and new growth.

“I love watching baby trees grow. Yes, it’s nice to come to places where trees are coming back,” she said.