California is losing redwood forests at unsustainable rate to wildfires, droughts

“If you can find a living tree, point it out,” said Hugh Safford, an environmental science and policy researcher at the University of California, Davis, while touring the damage from the Caldo Fire, the worst fire of the past decade. One of many large fires that occurred.

Dead pines, firs and cedars stretched as far as the eye could see. The fires burned so hot that, more than a year later, the soil in some places remains poor. Granite boulders were scorched and flaked off in the inferno. Long, narrow indentations mark graves of fallen logs that disappear in the smoke.

The destruction of this area of ​​the El Dorado National Forest may be permanent—part of a troubling pattern that threatens a defining feature of the Sierra Nevada that John Muir once called “the constant A wavy ocean of green trees.”

Scientific research shows that such forests are disappearing as increasingly intense fires alter landscapes across the planet, threatening wildlife, jeopardizing efforts to capture climate-warming carbon, and harming water supplies.

The culprits in the American West are a combination of factors: a century of firefighting, the elimination of indigenous burns, the felling of large, fire-resistant trees, and other management practices that suffocated forests with small trees, brush, and dead wood.

Drought has killed hundreds of millions of conifers or left them vulnerable to disease and pests and more likely to catch fire. Climate change is bringing more intense, larger, and less predictable fires.

“It boils down to a fuel jungle in a wooded area,” Safford said. “There’s a big plume of steam behind the fire there, and it can burn forever, forever.”

Despite relatively mild wildfire seasons over the past two years, California has seen 12 of the 20 largest wildfires (including the first eight) and 13 of the most destructive wildfires in the past five years. Record rainfall and snowfall this year have essentially ended a three-year drought, but explosive growth in vegetation could fuel future fires.

A recent study found that California’s tree cover has declined by more than 1,760 square miles (4,560 square kilometers) since 1985, or nearly 7 percent. Forest area increased in the 2000s, but has rapidly declined due to larger and more frequent fires. Research in the journal Advances of the American Geophysical Union.

A study of the southern Sierra Nevada, home to Yosemite, Sequoia and Kings Canyon national parks, found that nearly a third of the coniferous forests have lost their habitat due to fires, drought or bark beetles in the past decade. Has been converted to other vegetation.

“We’re losing them at a rate we can’t afford,” said Brandon Collins, co-author of the book. Report in the Journal of Ecological Applications Adjunct Professor of Forestry at the University of California, Berkeley. “If you continue at the same rate for the next 20 to 30 years, it will go away.”

Some environmentalists, such as Chad Hansen of the John Muir Project, sponsored by the nonprofit Earth Island Institute, say there is a “myth of catastrophic wildfires” supporting logging efforts – and he often files lawsuits to block the removal of dead trees or Sparse forest plan.

Hansen said seedlings are growing from the ashes of severe fires, and dead wood provides habitat for endangered spotted owls, Pacific fishermen and rare woodpeckers.

Hansen said his research has found that forests have always had dense trees and some serious fires, and he believes weather and climate change are causing fires to grow larger, while logging is making the situation worse.

“If everything people are hearing is true, then there will be more reason to worry,” he said. “But the public is being gaslighted.”

Others, however, worry that poor forest management could lead to severe fires that harm wildlife habitat, the trees’ ability to store climate-warming carbon and the quality of Sierra snowmelt that provides about 60 percent of the water for farms and cities.

Burn scars are more susceptible to flooding and erosion, and runoff can be contaminated with ash and sediment.

“Areas that are heavily burned by mixed conifers, those are all vulnerable to overall forest loss,” said Christy Brigham, director of resource management and science for Sequoia and Kings Canyon National Parks. “We don’t know what the impact of that will be. What that means for wildlife habitat, water cycles and carbon storage. And that’s not even getting into our love of forests.”

After wildfires in 2020 and 2021 destroyed about a fifth of the giant sequoias — once considered virtually fireproof — the National Park Service launched a controversial project last week to plant them in single groves. largest saplings to help these giant trees recover.

Changing forest landscape

Many researchers say the Sierra Nevada’s tree canopy has changed dramatically since heavy logging during the Gold Rush.

Before the mid-1800s, fires started by lightning or set by Aboriginal people burned millions of acres every year. It takes over the undergrowth, sending low-intensity flames along the forest floor and wiping out smaller trees that compete with larger trees.

“The charming openness of the Sierra forest is one of its most striking features,” said John Muir, describing how easily a horseman could move through the woods.

But after settlers drove out Native Americans and cleared forests, fighting fires became a mission to protect the precious trees, and more and more homes were built deep into the wilderness. In 1935, the U.S. Forest Service instituted a policy requiring that any fire be extinguished by 10 a.m. the next morning.

This has made the forest four to seven times denser than before, Safford said. While many of the larger fire-resistant trees, such as ponderosa and Jeffrey pines, are harvested for lumber, smaller trees that are less fire-resistant thrive. They compete for water, and low branches allow fire to crawl into the crowns of taller trees, creating devastating crown fires.

“John Muir wouldn’t recognize any of this,” Safford said during a tour last October, pointing to a patch of tightly packed dead trees. “He didn’t even know where he was.”

Flammables take off

Safford said the Caldo Fire destroyed 1,000 structures, burned through the Sierra Leone Mountains and into the Tahoe Basin, scorching forests that had not seen flames in more than a century. Years of drought caused by climate warming have made it a tinderbox.

Large swaths of the El Dorado National Forest burned so intensely that mature pine trees caught fire and killed their seeds. Unlike species such as giant sequoias and lodgepole pine, which cast their seeds into fire, the Sierra Nevada’s dominant pine trees cannot reproduce if their seeds burn.

Manzanita and mountain whitethorn (common shrubs in California’s lower elevations) take root in the ash and can dominate the forest.

Repeated fires or other disruptions can trigger such changes in ecosystems, the study found.

March research found that fire severity was increasing across 334 western wildfires and that dry conditions after fires made regeneration of major conifer species less likely, concluding that the problem could easily worsen as climate changes.

Along U.S. Highway 50, as the Caldo Fire continued to burn out of control toward Lake Tahoe, Safford parked his SUV, climbed a rocky knoll, and pointed down a bare slope. The forest there burned down in 1981 and was replaced by scrub.

Safford said the Caldor fire, allegedly started by a reckless father and son, may have exacerbated the situation. Recovery from severe burns will largely depend on whether another fire occurs in the next few years, he said.

forest management tools

To address the problem of massive wildfires, the federal government, which owns nearly 60% of California’s 51,560 square miles (134,00 square kilometers) of forest, reached an agreement with the state in 2020 to jointly reduce fuel use in 1,560 square miles (4,040 square kilometers) of forest. . ) one year to 2025.

Although only a small portion of the land needs to be dealt with, after years of inaction it is considered a promising development, albeit not without controversy.

Fire scientists advocate more intentional burning at low to moderate severity to clear vegetation that makes forests prone to blazes.

But before retiring in 2021, the Forest Service worked as a regional ecologist for 20 years. Safford said the Forest Service has historically been risk-averse. Officials often extinguish flames before they have the benefit of a low-intensity fire, rather than worrying about the possibility of a fire. .

In the weeks leading up to the Caldo Fire, the Forest Service had been monitoring the Lightning Fire south of Lake Tahoe while dealing with more pressing fires. But when the small fire caused millions of dollars in damage, politicians criticized the agency for not doing more. Officials quickly said they would no longer allow some naturally started fires to burn this season.

With more than $4 billion in funding from the Bipartisan Infrastructure Act and the Inflation Reduction Act, the Forest Service plans to increase forest thinning efforts in areas where wildfires pose the most immediate threat to communities and infrastructure.

This will include felling smaller trees and deliberately setting fires to remove accumulated forest debris.

Thinning Front

Last fall, when Safford led two graduate students along a rutted fire road through a charred forest, they discovered a land teeming with life, where tall pines and cedars towered overhead and seedlings sprouted.

Safford calls it “nirvana.” Before the fire, smaller fire-intolerant trees had been cut down and other vegetation cleared. The spaces between the trees allowed the fire to spread along the ground, charring only some trunks.

A coalition of conservation groups in Sierra Leone sent a letter to congressional leaders in 2021 urging more federal funding for fire protection capabilities. Their letter cited “broad consensus among fire scientists, land managers, firefighters” to increase thinning and prescribed fire.

Susan Britting, executive director of one of the groups, Sierra Forest Legacy, acknowledged that any clearcut would raise suspicions because loggers historically cut down the largest, most marketable trees. But she said thinning trees to a certain diameter is acceptable, although she prefers prescribed burning.

“In my experience, things like logging, clearing trees, and even reforestation happen,” Brittin said. “Prescribed fires that need to happen … are just delayed and put on hold rather than prioritized.”

A large green island on a fire severity map of the nearly 350-square-mile (906-square-kilometer) Caldo Fire illustrates the targets of prescribed burns. Green areas represent lower fire severity and correspond to areas where fires occurred in old trees in 2019.

The possibility of intentional burning — as happened last year in New Mexico’s largest fire in history — remains a major challenge to the strategy.

While managed fire and prescribed burns have broad support among scientists and environmental groups, thinning is controversial and often faces court challenges.

In a 2020 letter to Congress opposing logging, Hanson of the John Muir Project and more than 200 climate and forest scientists said some thinning can reduce fire intensity, but these actions typically require larger It is the trees that make them economically valuable.

Safford, now chief scientist at the environmental benefit company Living Planet, acknowledges that larger trees have been cut down in the past, but says that’s not envisioned in today’s thinning programs aimed at making forests healthier.

Even with a chainsaw, he said, we couldn’t solve the problem. Two-thirds of the rugged mountain range is inaccessible or closed to logging, so fire will do most of the work.

But there is resistance to using fire as a management tool. Homeowners worry that prescribed fires will spread over perimeters and destroy homes. Similar concerns have led fire agencies to contain small fires that could burn the forest floor.

“This is a classic evil problem, and any solution you come up with will have huge consequences for the rest of society and what people want to do,” Safford said. “So I’m worried that at some point we’re going to burn down all the forests.”