Jack Cohen, one of the country’s leading fire behavior experts, was on the other end of the telephone line. And he sounded irritated.

He was talking about a U.S. Forest Service study he authored three years ago that says the best way to protect homes from wildfires is to clear the vegetation immediately around them-—not to thin or burn forest on adjacent land.

Not long ago, a study like that would have attracted scant notice outside of a small circle of fire researchers in the federal government and academia. But in today’s overheated political climate, where environmental controversies are big news, Cohen’s research has drawn a good deal of attention.

Its current relevance is obvious: if you don’t need to cut trees in the forest to protect homes, then why is the federal government embarking on a $12 billion, fifteen-year effort to reduce fuel densities on 20 million acres of dense western forest to reduce the catastrophic fire threat to communities?

It is environmentalists, more than any other group, who have seized on Cohen’s study. Suspicious that the Forest Service is raising the alarm over the ignitability of western forests to revive its flagging timber program, they point to the Cohen study as proof that the National Fire Plan—the policy that lays out the justification for the massive cutting and burning effort—is a boondoggle in the making. The best way to deal with the catastrophic fire problem, they say, is if everyone simply cleans up their backyards.

“I agree and disagree” was Cohen’s curt telephone response—and, evidently, his way of making it clear that he has not been entirely pleased with the manner and frequency with which some environmentalists have trotted out his research before the media.

It’s not that he thinks they’re misrepresenting his work. It’s that he thinks they’re failing to make a crucial distinction—the threat wildfire poses to homes and other structures, and the threat it poses to forests. “Those are two very different things,” Cohen said.

To make his point, Cohen, who works at the agency’s Fire Sciences Laboratory in Missoula, Montana, cites two of last year’s most devastating conflagrations—the Cerro Grande Fire, which destroyed more than 200 homes in Los Alamos, New Mexico, and the collection of fires known as the Valley-Skalkaho Complex, which burned scores of homes while charring 306,000 acres in and around Montana’s Bitterroot valley.

In both cases, Cohen said, only a handful of the houses that were burned came in direct contact with the full-scale crown fire. The rest were ignited by red-hot embers hurled into neighborhoods by the main body of fire burning in the forest and by low-intensity ground fires that flared up violently when they hit overgrown backyards.

What that means, according to Cohen, “is that the ignition of homes is by and large not caused by the big flames that we pay attention to.”

But it is precisely those big flames that are scorching western forests with ferocious intensity. In one tragic afternoon in July, the Thirtymile Fire in Washington state’s Okanogan National Forest grew a hundred-fold—from twenty-five acres to 2,500 acres—and killed four firefighters. A blaze last summer that didn’t receive much notice, the Jasper Fire in South Dakota’s Black Hills National Forest, blew up and burned 50,000 acres in a matter of hours. The Valley-Skalkaho Complex was born in a single day, August 6, when eight fires merged into one massive firestorm. And Cerro Grande did not just leave behind homes burned to their foundations; it also left an eight-square-mile swath of incinerated forest marked only by scorched poles, a carpet of ash six inches deep and, here and there, tiny beads of glass where the soil was vitrified by air temperatures as high as 2,000 degrees.

Properly speaking, fires like these are infernos. Cohen has concerns—as do most fire scientists—about the ability of forests to recover from such blazes. In other words, Cohen does not think—as some environmentalists have argued—that it’s just houses that need to be saved. He thinks the forest needs to be saved as well, and he supports thinning and burning projects even if they take place well away from residential properties.

“My research indicates that even with these high-intensity fires you can make houses highly ignition resistant and still lose the forest,” Cohen said.

A TRICKY ISSUE

There’s no question that after decades of fire suppression, deadwood on the floor of some western forests has built up to unprecedented levels—as has the density of small, flammable trees. Timber industry claims notwithstanding, logging has increased the fire danger by drying out the forest, removing the biggest, most fire-resistant trees and leaving behind flammable slash piles. Livestock grazing has also eliminated the grasses that used to carry beneficial, low-intensity fires through the forest.

Whether that adds up to a situation so dire that the survivability of western forests is at stake is a tricky issue.

One reason for the trickiness is the trickiness of fire itself. Significant parts of the Valley-Skalkaho Complex, for example, were only lightly burned, and just 5 percent of the Clear Creek Fire in Idaho—the most massive blaze that erupted last year—burned hot enough to harm the soil (compared to 34 percent on the Cerro Grande Fire). Environmentalists have pointed to cases like these to make the argument that the fire danger is being overblown.

The fact that western forests are made up of different forest species adds another layer of complexity. The Thirtymile Fire and the famous 1988 Yellowstone fires burned as crown fires in dense stands of lodgepole pine, and in lodgepole pine forests, crown fires are a normal part of the ecosystem. Lodgepole evolved with crown fires and its cones remain in the canopy—for decades in some cases—waiting for a crown fire to come along. When one does, the cones open in response to the heat, and within days, seeds start to fall. After a crown fire strikes lodgepole, the burned forest floor is carpeted with the seeds, and before long, lodgepole saplings take root. Given lodgepole’s affinity for intense fire, it is probable that much of the area burned by the Thirtymile Fire will bounce back quickly—as has happened at Yellowstone.

The situation in a ponderosa pine forest is completely different. There, cones typically release their seeds upon reaching maturity. That adaptation works well when the only fires that burn through are low-intensity ground fires. Those fires, to some extent, destroy seeds that are scattered on the ground, but they don’t destroy the source of the seeds—the trees themselves. But when a crown fire roars through a ponderosa forest—as happened in the Cerro Grande blaze—the seeds and the trees are killed, leaving no way for a new generation to establish itself. “To a great extent, we don’t get ponderosa pine back after extensive crown fires,” Cohen said.

Just about everyone agrees that the ponderosa zone is in the deepest trouble—and for a simple reason. Because it used to see fire most frequently, every seven to ten years on average, it has been most altered by the removal of fire from the landscape. Instead of regular cleansing fires, ponderosa forests now see fire once every few decades, if that often. As a result, forests that used to be famous for their spaciousness—about twenty-five to eighty trees per acre—now are clogged with several hundred to as many as 2,000 trees per acre. That ponderosa forests have lost their natural fireproofing is a huge problem because of their nearness to population centers.

The extent to which forests have been altered by the exclusion of fire lessens as the altitude of the forest increases. Again, the reason is simple: the higher you go, the cooler and moister the forest—and the longer the “fire return interval,” to use the jargon of fire experts. Higher-altitude forests historically saw fire only every seventy-five to 100 to 200 years. Consequently, they have been little altered during the fire suppression era, which didn’t get under way in earnest until after World War II.

What this also means is that a crown fire in a high-altitude forest is no big deal in terms of that forest’s survivability—it evolved with stand-replacing events. The problem is that there is a greater chance now that such high-intensity blazes will not be limited to pockets of thick, high-altitude forests, as nature intended. Retired Forest Service fire ecologist Stephen Arno estimated in a recent study that 60 percent of the forests of the northern Rockies are now vulnerable to stand-replacing fires, compared to 20 percent historically. With the fuel buildup and the closing in of the canopy across broad swaths of the mid- to low-elevation forests, there’s a potential for crown fires on a scale no one has seen before. “There’s a potential for 100,000-acre crown fires,” said Craig Allen, a fire ecologist with the U.S. Geological Survey and a leading Southwest fire expert.

TO LOG OR NOT TO LOG?

Environmentalists cringe when they hear forest managers call for thinning projects because they think it gives license to federal land managers to get out the cut under the guise of reducing the fire danger. “Logging is the problem, not the cure,” said Chad Hanson of the John Muir Project, an organization dedicated to ending all commercial logging on public lands.

Hanson, like many environmentalists, acknowledged that there is a serious fire danger in the forest. And he offered a solution: remove brush and small-diamater trees, on the order of a few inches in diameter. He expressed adamant opposition to removing larger trees, such as those in the fifteen- to thirty-inch range, and said it is outrageous that some of the initial National Fire Plan “hazardous fuel reduction” projects call for doing just that. Logging trees that size actually increases the fire danger by breaking up the canopy and drying out the forest, Hanson said.

James Agee, a University of Washington fire ecologist, said it matters how the logging is done. If you thin an area but leave all the slash behind, “you’ve accomplished thinning but increased the fuels.” Similarly, if the canopy is opened too much by cutting, you’ve created an entry point for drying winds. He said logging can reduce the fire danger if it focuses on increasing the distance between ground vegetation (so-called ladder fuels) and the canopy, making it harder for fire to get into the treetops, and if “to some extent” it breaks up the canopy itself, impeding the ability of a crown fire to travel long distances.

Like Hanson, Agee agreed it was critical to focus on removing the most flammable material—brush and small-diameter trees—while leaving behind the biggest trees, which happen to be the most resistant to fire. But he said that removing a certain number of larger trees, even those with diameters of twenty inches or greater, makes good ecological sense. “Some of those trees came in after fire suppression and are part of the problem” in terms of excessive fuel loads, Agee said.

Agee also said that including a limited number of bigger trees in thinning projects makes economic sense because it creates an incentive for logging outfits. That’s precisely what Hanson and some other environmentalists don’t want to see because they say it will lead to excessive logging.

STORM CLOUDS

Lyle Laverty has a problem with that kind of thinking. “There are some elements that think any time it’s a commercial timber sale, it’s part of the evil forces out there. But it’s a positive thing.”

Laverty heads the National Fire Plan for the Forest Service. Dubbed “the fire czar” by the media, Laverty comes across a bit like President George W. Bush, affable, relaxed—and apparently unconcerned with the political spot fires developing around him. Here’s a sampling of some of the difficulties that are beginning to crop up as the Forest Service begins implementing the fire plan:

CONGRESSIONAL IMPATIENCE. In the wake of the Thirtymile Fire, Representative Scott McInnis, a Colorado Republican, criticized the Forest Service for not moving fast enough to reduce the fire danger. Since the fire, New Mexico’s Senator Jeff Bingaman, chair of the Senate Energy and Natural Resources Committee, attached language in July to the Interior Appropriations bill requiring that 60 percent of next year’s thinning and burning projects on Forest Service and Bureau of Land Management land be located within the wildland-urban interface.

“The senator wants to ensure that the area that should be the top priority [forested lands near communities] is getting addressed,” said Kira Finkler, an aide.

Laverty told Forest Magazinewhat he has already told Congress: only 25 percent of the thinning and burning projects this year will have been in the interface. That it isn’t a greater percentage, Laverty said, is due to the fact that virtually all of the projects being implemented now were planned eighteen months to two years ago—before the National Fire Plan, with its emphasis on protecting communities, had been thought of. Laverty said about half of next year’s projects will be in the wildland-urban interface.

There are two schools of thought regarding the wildland-urban interface and the way the Forest Service is going about implementing these projects. One, expressed by Steve Holmer of the American Lands Alliance, is that the agency is essentially ignoring Congress’s demand to focus on the interface and is “just willy-nilly doing projects.”

“They’re doing what’s convenient and easy for them to do,” Holmer said.

Laverty defended the approach, saying that although the primary focus should be in forests near communities, the agency is also seeking to reduce the fire hazard over a larger region to reduce the forest’s vulnerability to unnaturally intense fire. Agee, the University of Washington fire expert, agreed: “The National Fire Plan was not put together just to protect the urban interface. It’s really a broader attempt—particularly in our drier forest types—to achieve the long-term sustainability of the entire forest ecosystem.”

LOOMING ENVIRONMENTAL CHALLENGES. It appears unavoidable that implementation of the National Fire Plan will be delayed by challenges from environmentalists.

One battleground that’s heating up fast is in the Southwest, where the Forest Service is seeking to waive restrictions aimed at protecting the federally protected Mexican spotted owl in order to allow dozens of thinning projects to go forward. Activists are also alarmed about the potential impact of thinning projects in California’s Sierra Nevada range on imperiled species such as the Pacific fisher.

Other complaints have been raised against the National Fire Plan—such as that it directs far too much money to fire suppression. “They’re still jumping on every fire that pops up, and that’s what got us in trouble in the first place,” one critic argued.

Laverty said that as time goes by and the fuel loads on the forest are reduced through thinning and prescribed burning, there will be less need for fire suppression. “But until we get stand conditions down, there will be a major protection need.”

HOMES ARE THE KEY

There are many issues to focus on in the wildfire debate, and the chances of getting confused are great. But if, like Cohen, you distill it to homes on the one hand and forests on the other, things become simpler—and more clear.

For example, he knows that the thermal effect of big flames does not extend beyond forty to sixty feet and that at a distance of 100 feet an all-out crown fire can’t even scorch wood. He sees that the problem isn’t catastrophic wildfire, but, as he put it, “the incompatibility of our homes with the western fire environment.”

He knows that the ignitability of a home can be greatly reduced by removing pine needles from backyards and roof gutters, placing woodpiles at a distance from houses and replacing wood-shingle and tar roofs with metal. He sees people’s unwillingness to make their homes more fireproof as the real villain.

If that unwillingness were overcome, Cohen believes, the much larger problem of how to nurture back to health vast swaths of sick, overstocked forest could be tackled in earnest. “We typically think of wildland fire victimizing our residential developments. But I would submit that our highly ignitable homes are keeping us from getting to a sustainable condition in our forests.”