As California forests dry up, wildfire risks rise

If you don't know what to look for, you might not notice the dying pine trees along Tollgate Road in Idyllwild. If a tree's leaves are fading from green to brown, that probably means it's being eaten alive by bark beetles — and California's epic drought is largely to blame.

Across Southern California, trees are dying in unusually high numbers as the drought continues. Water-starved vegetation is finding it harder to stay alive, and many pine trees in the mountains surrounding the Coachella Valley don't have the strength to fight off bark beetles.

It's a potent combination that could stoke devastating wildfires over the next few months.

"Fires are going to burn more actively if we have fire in an area where there's a lot more dead fuels," said Tom Rolinski, a meteorologist and fire specialist at the U.S. Forest Service in Riverside. "Everything's just coming together for us to see a potentially busy fire season."

Wildfire risks are particularly acute in Idyllwild, a quiet town of several thousand people in the heart of the San Jacinto Mountains, west of the Coachella Valley. Dense pine trees and unruly wildlife cover much of the community, and bark beetles have attacked many of those trees over the past year, priming them to burn.

Idyllwild narrowly escaped the July 2013 Mountain Fire, which charred more than 27,000 acres in the surrounding forest. The fire came within two miles of the Palm Springs Aerial Tramway, blanketing Palm Springs with ash and smoke.

This year, Idyllwild might not be so lucky.

"Common sense tells us that if something is drier, it's more likely to burn," said Edwina Scott, executive director of the Mountain Communities Fire Safe Council, a nonprofit based in Idyllwild.

Already, state fire officials are reporting an uptick in wildfires in 2015.

California saw 1,278 fires through May 9, compared to a five-year average of 757 wildfires over the same time period, according to Cal Fire data — an increase of nearly 70 percent. This year's wildfires had burned 5,133 acres, compared to a five-year average of 4,805 acres.

Wildfires have always been more frequent and more severe during droughts, said Lynne Tolmachoff, a Cal Fire spokesperson. What's different about this drought is its severity.

"We hope this will be the last summer that we're sitting in this drought," Tolmachoff said. "But we have to prepare for the possibility that we're going to get a fifth or sixth year of drought."

Dying trees

This isn't the first time bark beetle populations have skyrocketed in Southern California.

The pests killed an enormous number of pine trees in the early 2000s, spurred by drought conditions. Those dead trees stoked the Old Fire, which scorched 90,000 acres in the San Bernardino National Forest in 2003.

In Idyllwild, that bark beetle outbreak was worse than the one underway right now, said Pat Boss, a former Forest Ranger and current project manager at the Mountain Communities Fire Safe Council. But the current outbreak is still getting worse. Boss, who has lived in Idyllwild for more than 60 years, had no trouble pointing out dying pine tree after dying pine tree as he walked down Tollgate Road earlier this week.

"It makes no difference how big the tree is, as far as its vulnerability for the beetle to attack it. Small tree, large tree, it makes no difference," Boss said.

Bark beetles are native to California, and under normal circumstances, they thrive by attacking old, diseased or damaged trees. Healthy pines usually fight them off, trapping the beetles in sticky resin and pushing them out through the bark.

During a drought, many water-stressed trees can't create enough sticky resin to expel the beetles. When that happens, the beetles multiply, sometimes killing a tree within six months.

"They just riddle it, like a shotgun," said Sheri Smith, an entomologist at the U.S. Forest Service in Northern California. "They attack it in multiple locations and overcome the tree."

The bark beetle infestation isn't the only way the drought is killing trees.

Over the first four months of this year, statewide precipitation is down nearly 60 percent from the 20th Century average, according to the National Climatic Data Center, and record-low snowpack spurred Gov. Jerry Brown to call for mandatory water cutbacks last month. With so little water to go around, many trees are dying without any help from bark beetles.

In the San Bernardino National Forest, 90 times more trees have been killed by bark beetles this year than were killed in 2013, according to preliminary U.S. Forest Service estimates. In the Angeles National Forest, 150 times more trees have been killed by bark beetles this year than were killed in 2015. In the Cleveland and Los Padres national forests, the differences are even starker.

Overall, more than 12 million trees have died in California's national forests since the drought began, the U.S. Forest Service estimates. For forest managers, it's an enormous but unsurprising number.

"It's no different than your grass, or your trees in the yard," Smith said. "If you run out of water, they die. It's pretty simple."

Forests ablaze

The July 2013 Mountain Fire still burns fresh in the minds of many Coachella Valley residents.

Sparked by an electrical equipment failure in the San Jacinto Mountains, the blaze tore through 22 square miles within two days, threatening the communities of Fern Valley, Idyllwild and Mountain Center. Nearly 6,000 people were ordered to evacuate, and Palm Springs residents were faced with unhealthy air quality as smoke and ash descended into the valley. It took firefighters 16 days, and nearly $26 million, to fully contain the fire. Just a month later, the Silver Fire scorched 20,000 acres.

Two other major wildfires have burned near the Coachella Valley over the past decade. In 2006, the Sawtooth Complex Fire charred about 70,000 acres in the High Desert, threatening Yucca Valley and Pioneertown. A few months later, the arson-caused Esperanza Fire burned more than 40,000 acres in the San Jacinto Mountains and killed five U.S. Forest Service firefighters.

Experts caution that it's difficult to predict wildfires, and that it's impossible to say with certainty how this fire season will compare to previous years. But the increase in dead trees brought on by the drought, experts say, makes it more likely that intense blazes like the Mountain Fire will strike.

"Once the tree is dead, it becomes dry, hot-burning fuel for any fire that comes through," Tolmachoff said.

This fire season is already shaping up to be intense.

Fire season typically lasts from June through October, but this year, it's already been underway for more than a month. Cal Fire has already increased staffing to levels that it typically doesn't reach until mid-July, Tolmachoff said. And plants aren't usually as dry as they are now until late June or early July, Rolinski said.

Max Moritz, a fire ecology and management specialist at UC Berkeley, described the combination of exceptionally low vegetation moisture and widespread plant deaths as "a double-barreled threat."

"On top of the dry conditions, it's been unusually hot in many, many parts of the state," Moritz said. "We do have a pretty exceptional fire season stacking up, or the potential for one."

Extremely wet years can create problems for California's forests, too. In some areas, heavy precipitation can cause more grass to grow, adding fuel for wildfires.

But history shows there are more wildfires, and more severe wildfires, during a drought. And climate change is likely to bring longer and more severe droughts, meaning Californians can probably expect longer and more severe wildfire seasons.

"To the degree that warmer temperatures make droughts worse — and they do — I think we can confidently say that climate change is going to lead to more conditions like this," Moritz said.

Thinning the trees

The drought isn't the only factor exacerbating wildfire risks in Idyllwild. The community is surrounded by thick forests and dense undergrowth — too thick and too dense, in the eyes of some experts.

"Every year, the plants grow taller, the chards grow denser. ... The question you need to ask is, what happens to these plants as they grow older and older?" asked Richard Minnich, a fire ecologist and professor at UC Riverside. "The fire hazard increases in the time since the last fire, because there are more years adding onto the fuel load."

Minnich believes the drought has done little to boost wildfire risks in upper elevations. Most fire experts disagree, but it's still possible that Minnich's proposals — cutting down more trees and allowing more "controlled burns" — would make Idyllwild safer during fire season.

"The forests are overgrown in some cases, making them more susceptible to large and damaging wildfires," Tolmachoff said. "Forests do need fires for their health."

The Mountain Communities Fire Safe Council educates residents on fire safety practices, and helps arrange grants for them to cut down dying trees, trim overgrown vegetation and fire-proof their homes. The U.S. Forest Service, meanwhile, creates "fuel breaks," stretches of cleared land around Idyllwild and nearby communities that slow the advance of wildfires.

For Minnich and others, those steps aren't enough. Without more controlled burns to thin out dense forests, areas like Idyllwild and Lake Arrowhead could "blow up at any time," he said.

"People in Idyllwild need to take responsibility for their own forest," he said. "That whole turn could burn from one end to the other right now, not a problem."

Idyllwild resident Mark Yardas has taken up Minnich's call to arms, proposing a biomass plant that would burn logged trees to convert them to energy. Yardas and a group of Idyllwild residents are looking for grant money, as well as possible locations to build the plant.

But their plan is still in its early stages, and it already faces skepticism. The Mountain Communities Fire Safe Council has looked at the idea, and Scott said it "doesn't seem like there is going to be the ongoing fuel to invest that much money."

The question of whether to allow more "controlled burns" is also controversial. Occasional wildfires are important for healthy forest ecology, and controlled burns can diminish the risk of severe wildfires. But knowing how much forest to allow to burn is far from an exact science — and all fires near human development are dangerous.

"Even though the forest may need the fire, we need to stop the fire in order to save lives and property and resources," Tolmachoff said.

Moritz believes that in the long run, Californians will need to rethink development patterns in response to wildfire risks. Areas like Idyllwild, he said, are hazardous places to build communities.

"If you want to talk about the problem, and how we got here, that's one thing. But the solution is a long-term change in how we live with fires," he said. "We're going to be forced to coexist with fire, and change the way we live in these fire-prone landscapes."

Sammy Roth writes about energy and water for The Desert Sun. He can be reached at sammy.roth@desertsun.com, (760) 778-4622 and @Sammy_Roth.

Dead trees

An unusually high number of trees are dying in Southern California's national forests, largely as a result of the state's historic drought. Here are estimates for the number of trees killed by bark beetles in the Angeles National Forest, the Cleveland National Forest, the Los Padres National Forest and the San Bernardino National Forest (which includes the San Jacinto Mountains) over the last three years:

Angeles National Forest

2013: 300

2014: 55,500

2015: 46,000

Cleveland National Forest

2013: 50

2014: 140

2015: 82,000

Los Padres National Forest

2013: 4,000

2014: 230,000

2015: 927,000

San Bernardino National Forest

2013: 300

2014: 2,250

2015: 27,000

The number of national forest acres where tree mortality has been observed is also up over the last three years:

Angeles National Forest

2013: 155

2014: 2,138

2015: 9,674

Cleveland National Forest

2013: 49

2014: 141

2015: 8,732

Los Padres National Forest

2013: 1,648

2014: 31,109

2015: 71,126

San Bernardino National Forest

2013: 186

2014: 1,478

2015: 6,393

Source: U.S. Forest Service