Are large forest fires ‘natural’ or huge, man-made sources of carbon emissions?
Posted on September 17th, 2008By John J. Fialka
Climatewire: This story is the first part of a two-part series about forest fires and climate change.
The afternoon of June 20 was the beginning of an epic, month-long nightmare for state and federal firefighters in Northern California. The stage was set by the driest spring in 100 years. Brush and the tangles of dead wood that often clog the region’s forests were tinder-dry. A heavy spring grass crop stood brown and parched in the valleys, leading like a fuse toward the wooded hillsides.
Then came nature’s match: the most severe dry lightning storm in the region’s recorded history. Six thousand lightning bolts ignited the grass and the forest, spawning more than 1,200 fires. Little fires merged into large fires, some of which were still burning a month later as 25,000 local, state and federal firefighters struggled to contain them.
Dubbed the “Lightning Siege” by the California Department of Forestry and Fire Protection, the event consumed 1.2 million acres of trees, killed 15 people, destroyed 511 structures and cost $85.3 million to put out. It also reignited a debate among scientists and regulators over the climate impacts of large fires and whether the state of California, which is busy writing protocols and creating incentives to reduce carbon emissions, should reward practices that can reduce the size of large fires, such as selective forest thinning.
Environmental groups have dominated this debate for years, arguing that forest fires are “natural” and should be allowed to burn if urban centers are not threatened. But new scientific research shows that recent forest fires aren’t like the fires of the past. They are often larger and hotter. They are huge generators of carbon dioxide and soot, two types of emissions that are changing the earth’s climate. Some research suggests these fires release about 5 percent of total annual U.S. greenhouse gas emissions, a contribution equal to about one-third of the transportation sector.
And as they devastate old-growth forests, ending their potential to store CO2, these mega-fires also liberate large quantities of mercury and create dioxin, both of which pose serious public health problems.
While there are few areas of agreement over what to do about this, officials generally agree on one thing: The current programs for fighting these fires are bankrupt. By mid-August, wildfires had burned through the U.S. Forest Service’s $1.2 billion annual budget for fighting fires, forcing the agency to scavenge at least $400 million from other programs. It was the fifth time in the last seven years. “We can’t walk away from fighting fire,” explained Joe Walsh, the agency’s spokesman.
Forest policy: a holy war with icons
Pressure groups that tend to frame forest issues in California sometimes resemble combatants in a religious war. Both sides use icons to make their impassioned arguments. Since the 1980s, environmental groups have used the plight of the spotted owl, an endangered species, to severely restrict the logging industry, which once engaged in thinning and clearing dead wood from the forests. In June, the “Lightning Siege” created a counter-icon.
One of the fires, called the Butte Lightning Complex, formed from 37 of these little lightning-strike fires. After feeling its way along a ridgeline where some forest thinning had been done to contain such fires, the blaze hit a 3-mile gap of U.S. Forest Service land where the thinning hadn’t been done. In the early hours of July 11, the fire roared down into the hapless rural town of Concow, incinerating much of it, leaving only cement slabs and twisted metal skeletons where 110 houses and trailer homes had been. Luckily, Concow had been evacuated, but one old man, who had survived previous fires, was sure he could survive this one. Firefighters found his body amid the ruins.
“This fire went through in less than an hour. After that it was a disaster. There were a lot of burned structures. The town was a wasteland,” said Scott McLean, a fire captain with the California Department of Forestry and Fire Protection (Cal Fire), who drove through the smoldering remains. “This was a firestorm. Nothing was going to stop it.”
What drives up the expense of fighting large fires is that they are often too dangerous to fight from the front. Cal Fire officials called for air tankers and helicopters to drop fire retardant and water on the blaze. But a temperature inversion held a thick blanket of smoke over the area. “The air tankers were grounded. When pockets opened up in the smoke, the helicopters got up, but then the smoke closed the pocket. They tried to go to another area, but they couldn’t find their water source,” explained McLean.
Frank Stewart, forester for the Quincy Library Group, a federally backed alliance of citizens, local officials and business groups that supports forest thinning projects in the eight-county area, blames environmental groups for the tragedy at Concow. Over the last 10 years, environmental groups have filed multiple administrative appeals that, according to the Forest Service, have delayed the projects’ implementation schedule. One project, called the Flea Valley project, was planned for the gap that the fire exploited to burn Concow, but it had yet to be implemented.
“Damn it, had we had it in, we may not have lost those 110 homes. You can’t guarantee that, but I just find it very frustrating,” said Stewart. “The West is just starving for a strategy to stop these fires, and it’s just amazing how these environmental groups have used these lawsuits to stifle one.” Stewart singled out the Sierra Forest Legacy, a Sacramento-based alliance of environmental groups that has filed numerous appeals and some lawsuits over aspects of the thinning.
Asked about Stewart’s claim, Craig Thomas, executive director of Sierra Forest Legacy, said it was “completely incorrect. We did nothing to stop the Flea project!” Before hanging up on a reporter, Thomas asserted that it was up to people in rural communities to “treat their homes and make them fire-wise.” As for the fire that incinerated Concow, he said: “That fire was natural. There is nothing unnatural about those lightning strikes!”
More recent fires may not be natural
Just what is natural and what isn’t about forest fires is a subject of long-standing and passionate political dispute, but experts have quietly begun to fill some of the scientific gaps. There is new evidence that the forests struck by the lightning in Northern California were anything but natural, compared with the forests of long ago. The federal and state-owned forests have been the subjects of years of conflicting political schemes, ranging from the federal government’s Smokey the Bear campaign, which suppressed the normal cycle of regular, but usually smaller forest fires, to the battle over the spotted owl, which suppressed logging.
The result has been forests packed with brush and dead wood that foresters call “fuel ladders” because they allow small fires to climb upward into the more flammable crowns of trees, an ignition that can create the cyclonic firestorms that spread flames and throw burning embers for miles. The thinned zones, where brush is removed and smaller trees are cut down, are designed to leave spaces between larger trees that save them by forcing the fires to come down to the ground, where firefighters can more easily snuff them.
One study, done by the U.S. National Center for Atmospheric Research, found that forest fires now contribute 4 to 6 percent of the man-caused greenhouse gases released in the United States each year. Christine Wiedinmyer, a chemical engineer and co-author of the study, believes it is the first comparison of its kind. She said because human forest-management policies are involved, states proposing reductions of greenhouse gases need to re-examine them. “If you’re trying to look at your carbon budget, you can’t neglect these fires.”
She noted that while the CO2 emissions from large fires are obvious, the tons of black soot particles released into the air by a large fire are also a cause of climate change because when soot precipitates out in polar regions — darkening the snow and ice — it accelerates warming.
A study of computer models made of several large forest fires shows that prior forest-thinning action can reduce the CO2 output by as much as 98 percent. One of the authors, Matthew Hurteau, a forest ecologist at Northern Arizona University, asserted that California’s current approach to accounting for the carbon release of forest fires ignores that possibility. The state’s Climate Action Registry tends to penalize forest thinning because removing brush and smaller trees creates some carbon emissions. Meanwhile, according to Hurteau, the state regards the massive release of carbon during forest fires as an uncontrollable event that no one is held responsible for.
Yesterday’s forests were thinner and more reliable for CO2 storage
Hurteau said a computer model designed to replicate what a Sierra forest looked like in 1865 suggests that older forests were much thinner and far more resistant to large fires than the current ones. “We’ve pretty much changed them,” he said, to the point where there’s a greater risk of storing carbon in a forest that has frequent fires.
One solution, he suggested, is that the state could reverse its policy and reward forest thinning with emissions-trading credits. The credits could provide the millions of dollars needed to support and promote forest thinning. Landowners who don’t thin, who risk fires that wipe out whole stands of older trees, might legitimately be penalized for carbon emissions under a state cap-and-trade system, he said, because the carbon has escaped into the atmosphere and the trees’ carbon-storing capability can’t be replaced for decades.
Michael Goulden, a professor of earth system science at the University of California, Irvine, compared current forests in California to measures made of them in a 1930 state survey and concluded that they are definitely different.
The older forests had experienced a natural cycle of smaller fires, in which the larger trees remained unburned. Old photographs show that the forests looked thinner, but Goulden’s students calculated that the bigger trees in them contained 26 percent more carbon than modern forests. “That was kind of a real surprise,” said Goulden. Seen from above, newer forests appear thicker, but competition from the thicket of smaller trees and brush has limited the size of larger trees. “It seems pretty clear today there are more trees, but fewer big trees.”
These findings have thrown a few curve balls at experts who contend that forests should be left alone because they store carbon and that current fires are “natural.” Stanley Young, a spokesman for California’s Air Resources Board, which is writing the accounting protocols for the state’s carbon reduction effort, says its experts are back at their drawing boards. They are examining what he called “carbon reversal,” or the possibility that what was regarded as a storehouse of carbon, such as a forest, could suddenly throw its inventory back up into the air.
One possibility is a risk assessment system, he said, which would grade forest lands on the possibility of large fires and focus incentives on those that are the least risky.
“We also have to consider previous fire suppression policies. This makes it a complicated issue,” added Young, “but we are shooting for something that could be ready this fall.”
Tomorrow: The 15-year brawl over forest thinning.