Fried to a Crisp: Why Some Experts Say We Must Burn the Trees to Save the Forests

By Glen Martin

The recent rains have blunted the psychological impact of California’s four-year drought, washing down the streets, perking up the landscaping, and heightening anticipation for a stormy El Nino-driven winter. We know, however, that one wet year is highly unlikely to end water shortages. What we may not fully grasp is that the damage done to the state’s forests is so far reaching that it may be permanent.

How bad is it? Really, really bad. Horrendous, in fact. Sally Thompson, an assistant professor in UC Berkeley’s department of civil and environmental engineering, cites the status of the state’s iconic giant sequoias as an example.  Thompson notes that Cal biology professor Todd Dawson has been monitoring the biggest trees on earth, “and has found that they’re extremely stressed. They’re dropping leaves—some of them may die. These are trees that have lived 3,000 years, enduring a wide range of environmental conditions, including other droughts. And now they’re being killed by this drought. That’s suggestive of what we’re facing. We’re heading into uncharted territory.”

And it’s not just giant sequoias. Virtually all of California’s trees are drought-stressed, and many are going down for the count. Thompson observes the U.S. Forest Service conducted flights over 8.3 million acres of woodland in the southern Sierra, the Central Coast and Southern California in April and concluded that about 10 percent of the conifers and oaks—about 12.5 million trees—had died in recent months. They had either expired directly from drought or succumbed to bark beetles, which attack weakened trees.

The situation has only grown more grim. Two weeks ago, Gov. Jerry Brown declared a state of emergency, warning that the U.S. Forest Service estimates “more than 22 million trees are dead and that tens of millions more are likely to die by the end of this year.” He asked for federal assistance and called for an accelerated program to cut and clear dead trees, expand the practice of prescribed burns and temporarily allow more burning of wood waste.

Greg Asner, a biologist with the Carnegie Institute for Science, used spectrometers and lasers to evaluate forest canopies on flights out of Sacramento and Bakersfield. The procedures yielded 3-D topographic displays that show the forest in varying shades of blue (healthy) yellow (somewhat stressed) and red (deeply stressed to dying or dead). Bottom line: There’s a lot of red in them thar hills. Asner concluded about 20 percent of California’s forests are doomed—up to 120 million trees.

The images reveal the trees are dying in a mosaic pattern, says Thompson.

“You’ll see patches of dying trees in the middle of healthier forest,” she says. “That’s probably due to such things as south-facing slopes or shallow soils. You’d expect such areas to experience (drought-related) stress first. But there’s a tremendous volume of dead wood building up all across the forests, and that’s pointing to a future that is potentially very scary.”

Such a vast accumulation of fuels could lead to wildfires that are perhaps unprecedented in their ferocity. They could be so intense and of such a vast scale that they could lead to broad “ecotonal shift” —the evolution of entire forests from one vegetative regime to another. Ponderosa pine forests, for example, could convert to chaparral fields.  Oak woodlands could change to grassy savannas. (As California previously noted, such ecotonal changes already may be occurring on Mt. Laguna in Southern California.)

That all sounds pretty apocalyptic no matter how you burn it, but Thompson observes we don’t have to just sit back and take it. It turns out there’s quite a bit that could be done to fireproof our forests—and perhaps increase water availability in the process. All it will take is a fair amount of money and political will.

“It’s clear that there is more standing biomass—trees—in our forests than existed before active fire suppression began a century or so ago,” says Thompson. “Studies show that the canopies are heavier, and the forests are more vulnerable to fire as a result.”

A little background: Prior to Euro-American settlement, California’s coniferous forests were characterized by extremely large, widely-spaced trees. Annals of the day—both textual and pictorial— made it clear that you could ride a horse through the forests unimpeded. There was little or no fuel (branches and dead trees) on the ground. The character of the forests was due to the occurrence of fire, both natural and human-induced; California’s natives burned the forests periodically to make hunting easier and encourage the growth of food plants, including acorn-bearing oaks, seed-producing grasses, and bulbs.

The good news: The forests of our forebears probably can be reclaimed. All we have to do is burn and cut down a lot of trees.

In the old days, fire noodled around in a low-energy fashion on the forest floors, killing insect pests, nibbling back the underbrush, and converting deadwood to ashes that ultimately nourished the great pines and firs. Today, wildfires rip through entire landscapes of closely-packed trees, immolating everything down to mineral earth.

“Ultimately, the fires can be so intense that they take out all tree seed sources,” says Thompson, “so the system shifts to chaparral.”

Today’s dense forests also have less biodiversity and suck up much more water than the forests of yesteryear. Thompson says studies of today’s Sierra Nevada forests indicate they transpire 35 percent more water—that is, extract it from the ground through the roots and transfer it to the air as vapor via foliage—than 19th Century forests.

The good news: The biologically rich, fire resilient and amply watered forests of our forebears probably can be reclaimed. All we have to do is burn and cut down a lot of trees.

“There are three ways to go about it,” says Thompson. “Mechanical thinning, prescribed fire, and managed fire.”

Mechanical thinning would be the removal of trees by chainsaws or heavy equipment. Prescribed fire would be controlled burning—setting blazes when fuels are relatively damp and conditions are cool and humid, allowing for fires that reduce the forest canopy without destroying every standing tree and living creature. Managed fire is basically letting nature run its course. Wildfires would be allowed to burn in unpopulated areas, ideally when weather conditions aren’t excessively hot and dry. The U.S. Forest Service is increasingly convinced of the wisdom of this approach. It recently inaugurated new management plans for three of California’s national forests, approving managed fire for 50 percent of their acreages.

Thompson and UC Berkeley professor of environmental science, policy and management Scott Stephens are working on a project in Illilouette Creek basin in Yosemite National Park that seems to confirm the healing properties of fire.

“The National Park Service backed off fire suppression and began using managed fire in the basin in 1973,” says Thompson. “Scott and I are seeing strong evidence for increased plant diversity in the basin. There’s much more meadowland and scrubland, and the resulting patchiness across the landscape reduces the risk for catastrophic wildfire. We’re also seeing greater diversity in water conditions. There are more areas with persistently wetter soils than were recorded under the old completely forested state. We’re now trying to determine whether these changes are increasing run-off from Illilouette Creek into the Merced River. “

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There are two important aspects to this situation: the need to train fire managers for controlled burning - timing of burns is very important if you don’t want to overdo. The windows of safe burning may be quite short. The public needs to understand what is happening and why. The “Let it burn” crowd would have you believe that summer fires are “natural” - they may be natural, but they also can be very hard on the forest in the long run - destructive of seed sources and soil damage!
hola resivan un coordial saludo. no saben como me gustaria saber y conocer de las tarifas de todo lo relacionado con su linda y hermosa universidad quiero conocer todo sobre las posibilidades de un colombiano emprendedor y con ganas de estudiar pueda tener el benecificio de estudiar en su univercidad gracias.
In the latter half of the nineteenth century, there was a great deal of grazing in the Sierra—this also removed fuel at the lower levels, kept meadows open, and thinned young trees. Herders, like Native Americans, burned often and kept things open. Grazing is not dangerous, and it is not expensive—prescribed burning can be both, especially when we have mixed houses and forest through poor land use planning. Yet foresters have a blind spot when it comes to grazing. Some say grazing causes some problems—believe me so does fire. Air quality, water quality, costly risk. At one point California had more escaped burns than any other state. Asthma suffers can have problems. Though it seems natural, burns are often done at quite unnatural times to reduce risk. We need more work on the use of grazing — it definitely worn’t work everywhere, but neither will prescribed burning. Ranchers will pay to graze, it does not cost millions of taxpayer dollars. This article does not talk about the difficulties of burning, but seems to take it as a panacea.
1. It’s just laughable to see the California drought routinely characterized as unprecedented or even record-setting. The state’s water authority keeps and publishes the records, and they show that the droughts of 1977 and 1924 were worse than the current one. The droughts of 1931 and 1934 were approximately equal to this one in severity, and the dry spell of the the 1980s through the early 1990s came close. 2. Here is additional research: See: “In California, A Wet Era Maybe Ending” “Analysis of tree rings suggests that western states have had many droughts of two decades or longer, including two megadroughts lasting longer than 100 years.” See: “What the West’s Ancient Droughts Say About Its Future” “A millennium ago—just yesterday, in geologic time—Native Americans waited all winter for rains that never came. They waited the next winter and the next. Then the marshes of their sacred San Francisco Bay turned from cattails to salt grass. Fishing declined and the Native Americans could no longer rely on the bounty of the bay. Finally, they left, hungry and thirsty, in search of water.” 3. Many of the droughts occurred LONG BEFORE Europeans set foot in the Americas and LONG BEFORE the Industrial Revolution!
Almost every claim that Mr. Martin makes is strongly contradicted by current science…many studies conclude that moderate and high intensity fire were active components of our western forests for millennia prior to European arrival, and carved out high severity fire patches in the landscape many thousands of acres in size, much larger that the largest patch in the Rim fire for example. The best designed studies regarding thinning and fire severity show that thinning actually encourages more high intensity fire, and causes widespread habitat disturbance and watershed damage in the process, not to mention costing millions and millions of taxpayer dollars. Mr. Martin is stuck in an old paradigm, and it appears he still has lots of company.
Re: thinning can result in increased distructive fires: suggested reading please? Thanks
In response to the request for studies about how thinning increases fire hazards: In 1987, 20,000 hectares burned in a wildfire in the Shasta-Trinity National Forest. The effects of that fire on the forest were studied by Weatherspoon and Skinner of the USDA Forest Service. They reported the results of their study in Forest Science. They found the least amount of fire damage in those sections of the forest that had not been thinned or clear-cut. In other words, the more trees there were, the less damage was done by the fire. They explained that finding: “The occurrence of lower Fire Damage Classes in uncut stands [of trees] probably is attributable largely to the absence of activity fuels [e.g., grasses] and to the relatively closed canopy, which reduces insolation [exposure to the sun], wind movement near the surface, and associated drying of fuels. Conversely, opening the stand by partial cutting adds fuels and creates a microclimate conducive to increased fire intensities.” (Weatherspoon, C.P. and Skinner, C.N., “An Assessment of Factors Associated with Damage to Tree Crowns from the 1987 Wildfires in Northern California,” Forest Science, Vol. 41, No 3, pages 430-453) In other words the denser the forest, the less wind on the forest floor, thereby slowing the spread of fire; the more shade on the forest floor, the less flammable vegetation on the forest floor and the more moist the forest floor All of these factors combine to reduce fire hazard in dense forest. Likewise, in a study of fire behavior in eucalyptus forest in Australia, based on a series of experimental controlled burns, wind speed and fire spread were significantly reduced on the forest floor. Thinning the forest will not reduce fire hazard. In fact, it will increase fire hazard. (Gould, J.S., et. al., Project Vesta: Fire in Dry Eucalyptus Forests, Commonwealth Scientific and Industrial Research Organisation and Department of Environment and Conservation, Western Australia, November 2007) And finally, here is a quote from the US Forest Service evaluation of the FEMA projects in the East Bay Hills which will result in a more flammable landscape: “Removal of the eucalyptus overstory would reduce the amount of shading on surface fuels, increase the wind speeds to the forest floor, reduce the relative humidity at the forest floor, increase the fuel temperature, and reduce fuel moisture. These factors may increase the probability of ignition over current conditions.”
As other commenters have already said, prescribed burns introduce another set of hazards that are not, on balance, safer than the problems they claim to solve. They pollute the air and often start wildfires. Unless you are a timber company, there is little logic in “thinning” a forest at a time when scientists predict that 20% of that forest is already dead or soon will be dead. The more living trees you kill, the more we are contributing to climate change. And the forests play an essential role in the water cycle by transpiring water from the atmosphere and returning it to the atmosphere as precipitation. Deforestation exacerbates drought. To suggest that trees are “soaking up water” is to devalue their ecological functions. If we must remove dead trees to reduce fire hazards, so be it. However, that should only be done in the Wildland-Urban Interface where property and human life is at risk because dead trees perform valuable ecological functions. They provide habitat for many species and they return nutrients in the soil. The cycle of the forest’s life should be left intact whenever possible. California’s landscapes are in transition because of climate change. We can’t use 20th century strategies in the rapidly evolving climate of the 21st century. The plants and animals that were native here when Europeans arrived at the end of the 18th century are no longer adapted to their native ranges. The landscape Europeans found had been “gardened” by Native Americans to feed, clothe, and house themselves for thousands of years. Plants and animals must move or adapt to survive and we are not helping them by attempting to freeze nature into some human fantasy of the past.
Mary, Thanks you for the reading study reference to the Forest Services’ studies. Warren