Greater Caution Needed Before Supporting Thinning, Biomass Projects

INTRODUCTION

The rush to formulate new forest legislation that advocates thinning forests, use of biomass for energy production, and the presumption that our forests are “unhealthy” and/or that large fires and beetle outbreaks are undesirable may soon create a new threat to our forests. There are a host of different bills before Congress including legislation introduced by Mark Udall of Colorado, Jon Tester of Montana, Ron Wyden of Oregon, among others that are all predicated upon a number of flawed or exaggerated assumptions.

Some of this legislation is better than others, and some of it even has some very good things in the language and policies that are an improvement over present policies. Nevertheless, there are many underlying assumptions that are troubling.

THE FIRE SUPPRESSION CONUNDRUM

There is a circular logic going on around the issue of fuel buildup and fire suppression. Currently the major federal agencies including the Forest Service and BLM generally attempt to suppress fires, except in a few special locations like designated wilderness. Despite the fact that most agencies now recognize that wildfires have a very important ecological role to play, we are told by managing agencies that they must continue to suppress fires or face “catastrophic” blazes—which they consider to be “uncharacteristic”.

The problem is that thinning won’t solve the “problem” of large blazes because the problem isn’t fuels. By allowing the timber industry to define the problem and propose a solution we have a circular situation whereby the land management agencies continue to suppress fires, thereby presumably permitting fuels to build up, which they assert thus drives large blazes, creating a need for more logging and fire suppression. This cycle of fire suppression, logging, grazing, and more fire suppression has no end.

In addition, since thinning reduces completion, opens up the forest floor to more light, thus new plant growth, thinning can often lead to creation of even more of the flashy fine fuels that sustain forest fires. Unless these thinned stands are repeatedly treated, they can actually acerbate fire hazard by increasing the overall abundance of the very fuels which are most problematic—the smaller shrubs, grasses, and small trees that sustain fire spread.

In addition, thinning can increase solar penetration leading to more rapid drying and greater penetration of wind—both factors that aid fire spread.

This is not unlike the approach taken with predator control, whereby agencies for years have shot, poisoned, and trapped coyotes in the belief that they were reducing coyote numbers. But since coyotes respond to such persecution with greater fecundity, predator control becomes a self fulfilling activity whereby predator control begets more predator control.

While fire suppression (and logging, grazing, and so forth) may be a contributing factor in fire spread in some forest types (primarily ponderosa pine), they are not ultimately what is driving most large fires. Large blazes are almost universally associated with climatic features like severe drought, wind, and ultimately by shift in oceanic currents such as the Pacific Decadal Oscillation. Therefore fuel reductions will not substantively change the occurrence of large blazes.

Even if one wanted to buy into the fuels-is-driving- large blazes story, it would behoove us to rethink the range of solutions. The National Park Service, the only agency that does not have a commercial logging mandate, has effectively dealt with fuel reductions through wildlands fire and prescribed burning. At the very least, any fuel reduction that may be needed should be done by prescribed burning.

QUESTIONING FIRE SUPPRESSION

One of the underlying assumptions of all these pieces of legislation is the idea that our forests are unhealthy and possess unnatural fuel loads due to fire suppression or fire exclusion. There is, of course, a bit of truth to the generalization that some forest types may have had some fuel build ups as a consequence of fire exclusion, but whether these fuel build ups are outside of the historic range of variability is increasingly under scrutiny.

It’s also very important to note that the majority of all forests/plant types in the West like lodgepole pine, subalpine fir, aspen, juniper, red fir, silver fir, Engelmann spruce, western red cedar, Douglas fir in west coast ecosystems, and many others have such naturally long fire intervals, that suppression, even if it were as effective as some might suggest, has not affected the historic fire frequency.

Indeed, the majority of acreage of forest types burned annually tend to be characterized by moderate to severe fire, and are not the forest types where fuel build up is presumed to be a major problem—namely ponderosa pine forest type. Yet most people apply the ponderosa pine model of less intense frequent fires to all other forest types and thus assume that fire suppression has created unnatural fuel levels.

In particular the timber industry has adopted the convenient theme that fire suppression has created a presumed “fuel build-up” responsible for large wildfires. (Never mind that there were always large wildfires long before there was any effective fire suppression—for instance, the 1910 Burn which charred more than 3 million acres of northern Idaho and western Montana)

Thus logging proponents have created a “problem” namely fuel build up, and then by happy coincidence, have a solution that just happens to benefit them-- logging the forest.

Fire suppression may have influenced some low elevation dry forests like those dominated by pure ponderosa pine, but perhaps not nearly to the degree or over the large geographical area that timber interest and logging proponents try to suggest. Those who want to justify logging try to conflate low elevation forests with all forest types—many of which such as lodgepole pine—are very likely not affected by fire suppression due to the naturally long intervals between fires in these forests.

CLIMATIC DRIVERS OF LARGE BLAZES

The emphasis on fuel reductions has obscured the fact that nearly all large blazes are climate/weather driven events. Evidence is building that wet, cool climatic conditions may be more responsible for dense forest stands and/or lack of fires than anything to do with fire suppression. In other words, fire suppression may not be as effective as some suggest and any fuel build up may be within natural or expected range.

In addition, there is also a growing body of scientific analysis that calls into question the very methods and conclusions used to construct fire histories. These analyses suggest that historic fire intervals, even in lower elevation dry forests like ponderosa pine, are biased. Fire intervals may be far longer than previously assumed. Because of this longer fire interval, dense forest stands may be natural, and/or no different than what existed in the past. There is also new evidence for mixed “severity” (i.e. moderate change) fires as well as crown fires in these dry forests. The implications of these findings is that many forests, even low elevation forests, may well be within the historic range of variability.

LARGE BLAZES NECESSARY

One of the issues missed by thinning proponents is that the vast majority of all ecological work occurs in a very small number of fires—the big so-called “catastrophic” fires. Even though most agencies and environmental groups now profess to believe that wildfire is important to healthy forest ecosystems, they are not willing to let fires do the work.

For example, in the years between 1980 and 2003, there were more than 56,350 fires in the Rockies. These fires burned 3.6 million hectares (8.64 million acres) Most of these fires were small—despite all the fuels that has supposedly made conditions in forests ready to “explode”. Out of these 56,350 fires, the vast majority of blazes totaling 55,228 fires or 98% of all blazes only charred 4% of the acreage.

On the other hand, a handful of fires—1,222 or less than 2% of the fires accounted for 96% of the acreage burned. Even more astounding is that 0.1% of the fires or about 50 fires charred more than 50% of the acreage burned.

This suggests four things to me. First, fuels are not driving large blazes. There is plenty of fuel throughout the Rockies, but most fires never burn more than a few acres—despite all the fuels that is sitting around. Fire suppression if it was responsible for a fuels build up doesn’t appear to be creating a lot of big fires.

The few very large fires that everyone is concerned about occur during very special conditions of drought, combined with low humidity, high temperatures and wind. And these conditions simply do not occur very often. When they do line up in the same place at the same time than you get a large fire—no matter what the fuel loading may be. My conclusion is that large blazes are climate driven events, not fuels driven.

Finally, the take home message for me is that even if we were successful at stopping big blazes through thinning and/or fire suppression, we would be in effect eliminating fire from the landscape. Since almost everyone today at least professes to the goal of restoring fire, than we have to tolerate the few large blazes—not try to stop them. Of course, it appears that despite our best efforts with logging, thinning, and all the rest, we have not had that much influence on eliminating the large blazes.

FRAMING THE ISSUE

One of the other major problems I have with the way many organizations have chosen to work on these issues is the way they “frame” the issues. When words like “working landscapes”, “restoration” , “unhealthy forests” “catastrophic blazes” “beetle outbreaks” are used in any discussion related to forests, they solidify in the public’s mind that there is a major problem with our forests, and more importantly that the “cure” is some kind of major invasive manipulation of forest ecosystems.

One must be careful about how you frame this issue. Even though most environmentalists do not support large scale commercial logging of our national forests, and have a lot of sidebars on how any logging should be done to address ecological concerns, when environmental groups say things like “we need to maintain our timber industry to restore the forests” the public just hears that our forests are a mess and the ONLY solution is more logging. I maintain that is not a message environmentalists want to be conveying. The public does not hear the sidebars, nor the cautionary words, rather they hear that we need to log our forests, and do so in a big way or ecological Armageddon is about to befall the West.

WHAT IS PRUDENT BEHAVIOR?

There is an important lesson in science called the precautionary principle. In the absence of full understanding of a problem, it is usually best to prescribe the least invasive and least manipulative actions. Conservation groups would be wise to apply this principle to forest policy.

That doesn’t mean I don’t support some “restoration” activities. To make an analogy, let’s look at the issue of wolf restoration. Putting wolves back on the land restores predation influences, but this is a very different thing than allowing hunters to kill elk. Especially because it allows the wolves, and natural conditions like drought, etc. t o determine what is the “right” number of elk and deer, not some agency with an agenda to sell licenses. Hunters influence elk differently than wolves and logging is different than say fires. Just as an elk killed by a wolf leaves behind carrion that other animals can use, a forest with fire leaves behind a lot of biomass that helps to sustain many other functions in the forest.

Logging short circuits those ecosystems functions. As with hunting whenever you have a commercial enterprise involved in natural resource policy, it distorts the conclusions and it’s convenient to ignore anything that suggests the activity—whether hunting or logging is creating problems.

NEW PARADIGM

There is a growing challenge to many of the assumptions about fires and its influence on forests. These challenges to assumptions about constitutes forest “health” and the historic role of large blazes and beetle influences is not unlike the challenges to common assumptions about predators that began with people like Adolph Murie, George Wright, and other scientists back in the 1930s and 1940s who started to question predator policy. These early ecologists were not only challenging politicians and citizens, but many other scientists who were advocates of killing predators to create “healthy” populations of deer and elk.

I need not remind many conservationists that there are still plenty of scientists around that will support killing predators like wolves, despite decades of research about the ecological need for top down predators. So assurances that any logging on public lands will use the “best” science are not reassuring to me. When there is a commercial/economic aspect to any management, that tends to distort and often compromise the science and scientists that are consulted. It would naïve for anyone to believe that this is any difference when dealing with fire and forest policy issues, especially when there’s an economic benefit to some industry and/or individuals for the policy.

QUESTIONING SUPPRESSION

There is a growing scientific body of work that is challenging the notion that fire suppression is responsible for dense forests and/or that crown fires, even in low elevation forests consisting of ponderosa pine and/or Douglas fir. The implications of this for forest policy are significant for if this is correct, our current conditions are not outside of the historical normal range of variability, especially when you consider past climatic conditions that are similar to the current dry, warm conditions.

One can find plenty of scientists who think our forests are out of whack, and prescribe logging to reduce fuels and so forth, however, if one is monitoring the scientific literature one would find enough evidence here and there to question the current assumptions about “forest health” and the presumed need for logging.

At the very least, it would seem a prudent approach to avoid endorsing logging when there is at least some evidence to suggest that our forests are not as out of whack as previously assumed, and/or that logging cannot do what advocates suggest—like restore the ecosystem or prevent large blazes.

PROBABILITY OF FIRES

Another unchallenged assumption of those prescribing thinning to protect say old growth ponderosa pine is the idea that somehow without thinning, we would lose all the old growth to fires. However, that ignores the low probability that any particular acre of land will burn in a fire. For one thing, most fires are small as mentioned earlier. They do not burn more than a few acres and go out. The few fires that do grow into large blazes occur under very special climatic/weather conditions of extreme drought, high wind, low humidity and high temperatures. These conditions do not occur that frequently, and to this you must provide an ignition. So even if you have drought, wind, low humidity, etc. you may not get a blaze.

In addition, even big blazes do not consume all the forest. Most large fires burn in a mosaic pattern for a host of reasons, the likelihood that any particular acre of old growth will burn is extremely small.

Finally, since thinning effectiveness even under the best circumstances rapidly declines over time, in order to protect old growth stands, thinning of that particular location in a forest must be very recent otherwise new growth generated by the opening of the forest, reduced competition, etc. often negates any advantage created by forest manipulation (logging).

LOGGING IS NOT BENIGN

Even if one disagreed with these new insights and interpretation of forest an ecosystem, and the presumed effectiveness of thinning projects, that doesn’t necessarily lead to logging as the “cure”. It wasn’t that long ago we heard many groups outlining the many ways that logging created ecological outcomes that were undesirable—the spread of weeds, changes in the abundance of snags, and down wood, that human activity in the woods disturbs and displaces sensitive wildlife, that disturbance of the land and use of logging roads (even temporarily logging roads) adds sediments to our streams, and so forth. Most of those critiques are still valid today, but we don’t hear that kind of criticism coming from many environmental groups anymore. This silence and unwillingness to continuously remind the public that logging has many, many negative impacts on forest ecosystems has compromised the environmental effectiveness as defenders of our public forests. After all who is going to assume that role if environmental groups do not continuously remind the public that logging has many unexamined and ignored externalities.

LESS MANIPULATE ALTERNATIVES EXIST

Even if one did not want to challenge the common perception that we have an “emergency” as Senators Wyden, Udall, Tester and others proclaims, logging isn’t necessarily the only or the best way to address this presumed emergency.

The National Park Service does fuels reductions and ecosystem restoration without logging. They have a long track record demonstrating that one can modify fuels and restore the ecological value of wildfire to the landscape without logging, and without jeopardizing communities. Yosemite NP, for instance, does prescribed burning in the crowded Yosemite Valley as does Muir Woods adjacent to Muir Woods, as well as many other national parks. That is not to suggest that prescribed burning will alleviate all concerns, but at the very least, it should be the approach that environmentalists advocate. Prescribed burning combined with natural wildfire can “restore” forest resilience as well as reduce fuels. Such an approach avoids many of the negatives associated with commercial logging, including the need for roads, the disturbance of water drainage by roading, soil compaction, removal of biomass, and so forth.

REDUCE HOME FLAMMABILITY AS FIRST DEFENSE AGAINST FIRE

There is an abundance of evidence to suggest that if community security is a concern, the best way to achieve that is through reduction of flammability of homes and the area immediately around the community, not wholesale logging for the forest ecosystem. Jack Cohen’s research at the Missoula Fire had demonstrated that thinning the forest is not the best way to protect homes.

Advocating for logging as the “cure” is like suggesting that the best way to reduce elk herds is by hunting, instead of being an advocate of wolf restoration. Any time you get an economic activity involved in natural processes you compromise the integrity of the goals and measures.

ADVOCATE FOR NATURAL PROCESSES

Even if the majority of you believe our forests are out of whack and are unwilling to accept the critiques from those who suggest that our understanding of forest ecosystems may be incorrect, that doesn’t mean one has to be a hand maiden for the timber industry. Nature does the best management—that is why we all are advocates for wilderness—we believe that allowing wild places to determine what is right for the landscape is the best way to preserve “healthy ecosystems”. If the forests are overstocked as some may want to conclude, than let natural processes select which trees should survive and do any thinning that is necessary using insects, disease, drought, fire, wind storms, and all the other mechanisms that regulate plant communities—and Nature will do a far better job of determining which trees should survive than any forester.

Our role as humans is to get out of the way as much as possible, not to intrude and advocate for invasive solutions like logging. The only role for logging on public lands that I see is to strategic as listed below.

WHEN TO SUPPORT LOGGING/THINNING

If you must support logging, make sure it is very limited, and framed not in terms of forest health, but as a useful way to reduce human anxiety. Logging around houses and communities to reduce public anxiety over fires may be a political necessity. A fire break of significant size around the perimeter of a community may reduce public fears about large fires; however, as has been shown in numerous cases around the West fuel breaks alone will not ensure that homes are safe. Flammability of individual homes must be addressed.

Praise for the Dead

http://www.fseee.org/forestmag/1102wuer.shtml

By George Wuerthner
Forest Magazine, Spring 2009

Dead. Most of us have negative associations with the word. After all how did Death Valley get its name? Not because it was a favorite vacation spot for prospectors. Is anyone interested in fishing the Dead Sea? And when we say someone looks like “death warmed over,” it’s not usually taken as a compliment. So it’s not surprising that most of us tend to view dead things as undesirable, unless we are talking about mosquitoes and rattlesnakes.

We impose this cultural bias about dead things to our forests as well. Public land management agencies spend billions annually trying to contain wildfire and insect outbreaks based upon the presumption that these natural processes are destroying the forest by killing trees. Even though there is now some grudging acceptance by land managers that wildfires and insect attacks may be potentially beneficial if they do not kill too many trees, stand-replacement fires, ice storms and large beetle outbreaks are still viewed as unnatural and abnormal—something to suppress, slow and control.

When these natural processes kill trees, managers propose logging to “salvage” the economic value of the downed trees. They operate on the tacit assumption that surplus wood can be removed without hurting the forest’s ecosystem, and until now that has formed the basis of scientific and/or sustainable forestry.

But a new perspective is slowly taking root among forest managers, based on growing evidence that forest ecosystems have no waste or harvestable surplus. Rather, it seems that forests reinvest their biological capital back into the ecosystem, and removal of wood—whether dead or alive—can lead to biological impoverishment. Large stand-replacement blazes and major insect outbreaks may be the ecological analogue to the forest ecosystem as the hundred-year flood is to a river. Such natural events are critical to shaping ecosystem function and processes. Scientists are discovering that dead trees and downed wood play an important role in ecosystems by providing wildlife habitat, cycling nutrients, aiding plant regeneration, decreasing erosion and influencing drainage, soil moisture and carbon storage.

“When you start to look at western forests outside of wildernesses and parks, you notice right away that they lack large quantities of downed wood—dead trees,” says Jon Rhodes, an independent consulting hydrologist in Oregon. “Ecologically speaking, there is a big difference between areas that have been logged compared to areas that are left alone.”

Chad Hanson, a University of California, Davis, researcher, agrees. “We are trapped by an outdated cultural idea that a healthy forest is one with nothing but green trees. An ecologically healthy forest has dead trees, broken tops and downed logs.” Such forests may not look tidy from the perception of a forester, he says, but it’s an indication that the forest is healthy and biologically diverse. “Pound for pound, ton for ton, there is probably no more important habitat element in western conifer forests than large snags and large downed logs,” Hanson says.

Studies have consistently concluded that most western forests have a deficit of large snags and downed dead wood. “Large standing trees are important,” Rhodes says, “but they shouldn’t be museum pieces. They should be part of functioning ecosystems.” When old-growth trees burn in wildfires, they aren’t completely lost, he says, but provide the ecosystem with large quantities of snags and downed wood. “While some say we can’t afford to have old growth burned by fire, it’s apparent that we can’t afford for old growth not to burn in fires, due to the importance of large snags and downed wood and its current lack in western forests,” he says.

Writing in a 2004 article in Conservation Biology, University of Montana ecologist Richard Hutto sums up the new thinking about the ecological value of dead trees. “I am hard-pressed to find any other example in wildlife biology where the effect of a particular land-use activity is as close to 100 percent negative as the typical post-fire salvage-logging operation tends to be,” he wrote. “Everything from the system of fire-regime classification, to a preoccupation with the destructive aspects of fire, to the misapplication of snag-management guidelines have led us to ignore the obvious: we need to retain the very elements that give rise to much of the biological uniqueness of a burned forest—the standing dead trees.”

Healthy Dependence

Dead trees are important to wildlife. Think woodpeckers. But many other species depend on dead trees and downed wood for food and shelter.

Hutto reports that upwards of 60 percent of species that nest in severely burned forests use only snags for nest sites. In addition, about 45 percent of all North American native bird species rely on snags for at least a portion of their life cycle.

Hutto has found fifteen species that are most abundant in forests with high numbers of snags resulting from high-intensity stand-replacement crown fire—the kind of fires that foresters pejoratively call catastrophic. Hutto notes it is doubtful that these species would have evolved such dependency on snag abundance if large stand-replacement fires and widespread insect outbreaks were uncommon or unnatural, as some suggest.

But it’s not just the use of snags for nesting, or even feeding as with woodpeckers, that attracts birds and other wildlife to recently killed forests. Burned forests also are used extensively by seed-eating species that are attracted by the abundance of new seeds shed by cones and colonizing plants.

Even the presumption that large blazes are a threat to spotted owls is being challenged. “There are several studies which indicate that spotted owls actually benefit from substantial patches of high-severity fire within their home ranges,” says researcher Hanson. “They selectively forage in unlogged, high-severity burn patches.” However, he adds, if these burned areas are salvage logged, spotted owls avoid them.

In a paper presented at a conference on the ecology and management of dead wood in western forests, researcher Timothy Kent Brown estimated that two-thirds of all wildlife species use dead trees or downed wood during some portion of their life cycle. Among Pacific Northwest vertebrates, sixty-nine species depend upon cavities for shelter or nesting, while forty-seven other species are strongly associated with downed wood. And it’s not just the obvious species like woodpeckers that demonstrate this dependence. Many bat species, for instance, hide in cavities in dead trees or under the loose bark of dead and/or dying trees.

Jim Andrews, a professor at Middlebury College in Vermont, studies amphibians and reptiles in northeastern forests. “Foresters tend to look at the forest from the floor up,” he says. “I have occasionally gone on field trips with them, and they were rather proud of how they had managed their forests, but the forest has nothing in it. There’s no cover. No places to find live critters.”

Andrews notes that dead and dying trees are important for many cold-blooded species, from gray frogs to arboreal rat snakes. “Standing snags, once they get big enough so that they have hollow centers—what foresters call ‘overmature’…are the places where wildlife reside,” Andrews says. “To a biologist you don’t have overmature trees—you have wildlife habitat.”

Andrews notes that the greatest biomass of terrestrial vertebrate species found in eastern forests are salamanders, not the more charismatic large mammals like deer and moose. Salamanders provide food to many other species, from wild turkeys to shrews.

But salamanders are also significant predators in their own right, Andrews says. They eat beetle larvae, fly larvae, ground beetles, spiders, sow bugs, round worms and other invertebrates that feed on forest debris. In doing so, they shape the forest ecosystem much as wolves do on another scale. “Salamanders, by preying upon these species that consume leaf litter, help to maintain a deeper layer of leaves and other organic debris that holds moisture, reduces floods and that kind of stuff,” Andrews says.

SMALL BUT CRUCIAL

It’s easy to identify an ecosystem for its most photogenic species, but there are dozens of small cogs that are of equal importance. One of those is ants, and downed logs are their preferred home. Ants are among the most common invertebrate in forest ecosystems and, not surprisingly given their abundance, are critical elements in forest ecosystems.

The most obvious value of ants is as food—from birds such as flickers to much larger animals like bears. In fact, research suggests that ants are among the most important food for bears in Oregon during June and July, as well as later in the summer if the berry crop is small. A British Columbia study found that grizzly bears rely on ants for food late in the fall when berries are unavailable. Reducing the number of dead trees, and thus ants, has a direct consequence for bear survival.

But ants also prey on insects that attack trees. For example, studies in Washington and Oregon discovered that ants accounted for an 85 percent reduction of pupae from two tree-defoliating moths.

Dead logs and snags are also home to pollinating insects. Solitary and colonial bees, of which there are hundreds of species that reside in downed logs and/or snags, are among the major pollinators of flowers and berry-producing shrubs.

Dead trees are even important for other plant species. Bureau of Land Management botanist and lichen expert, Roger Rosentreter, says that dead snags, by creating suitable habitat for lichen growth, carry the legacy of lichen species to the next generation of live trees in the forest. Research by Oregon State University professor Bruce McCune found that some common lichens were more abundant on barkless branches of dead trees than on live ones.

Healthy forest soils also require decomposing material. Below the litter layer in the soil is yet another layer of life that depends on dead wood. “There’s a whole complex food web in the soil that is a combination of bacteria, fungi, protozoa, micro-fauna like arthropods, springtails, mites—all those organisms thrive and are important to the composition of the forest,” says soils specialist Tom Deluca, a forest scientist at the Wilderness Society’s Northern Rockies office.

Deluca notes that while forest litter, such as fallen needles and branches, is important to forest soils, forest soil development is also “very dependent upon the influx of carbon from [whole] trees that have a life cycle of hundreds of years.”

If the carbon influx (dead trees) created after a wildfire or beetle outbreak are removed, he says, the soil is robbed of energy for micro-organisms. “The organic influx is essential to micro-community,” he says.

MICRO-SITES

People commonly assume that wildfire destroys trees and leaves a smoldering pile of ashes. In truth, some live trees and a lot of dead wood physically survive blazes. Beyond the value of dead trees as feeding, hiding and resting habitat for wildlife, downed logs play an important role in forest regeneration.

Snags and downed logs modify micro-sites that can affect seedling establishment. For instance, snags provide some shade and reduction of drying winds, creating more favorable conditions for tree seedling survival. Researching the effects of fires on snags in Wyoming, Dan Tinker, of the University of Wyoming, found that only 8 percent of the downed wood was consumed in fires. He also says that 35 percent of the downed wood in clear-cuts was a biological legacy left by past fires that occurred prior to logging. Tinker and his associates found that these legacy trees intercepted precipitation and funneled it to the ends of the log, creating a moister micro-site that was often more favorable for tree seedling germination and survival.

Other researchers have found that, when it comes to trees, all death is not equal. How a tree dies affects its ultimate role in the forest ecosystem. A tree killed by bark beetles has a different decay trajectory than, say, a tree dying from disease or wildfire. For instance, bark beetles, by breeching the outer bark of a tree, create tiny openings that allow fungi and other insects to enter the tree’s core.

Bark beetles emit pheromones that not only attract other bark beetles but also insects that prey on bark beetles. And the volatiles released from the decomposing trees attract another entirely different group of organisms that feed upon dead wood. That is why one researcher in Europe found that bark beetle outbreaks increased biodiversity in forest ecosystems.

William Laudenslayer, a U.S. Forest Service researcher at the Pacific Southwest Forest and Range Experimental Station, and his colleagues experimentally girdled trees to kill them, a common forestry practice used to produce snags for wildlife. They compared those snags to trees killed by bark beetles. They found that “bark beetle-killed trees provided significantly greater woodpecker feeding activity, cavity building and insect diversity” compared to snags created by girdling.

Trees heated and killed by fire create sapwood that resists rotting and lasts longer in the ecosystem. Trees dead prior to the fire tend to become blackened and charred. Charred trees are also resistant to decay. Thus, a wildfire creates long-lasting biological legacies that can survive for a century or more.

DEAD IN THE WATER

Wayne Minshall, professor of ecology with the Stream Ecology Center in the Department of Biological Sciences at Idaho State University, points out the importance of logs to aquatic ecosystems as well. “Wherever the logs occur, they cause the stream to meander or braid. And whenever you get braiding or meandering, you’re getting a reduction in the power of the stream and delivering the water in a way so as to dissipate that energy so the flow becomes less destructive. That’s important in keeping streams healthy.”

Wildfires and/or insect outbreaks create downed logs that fall into streams and across slopes. Downed logs, by slowing the velocity of the water, allow sediment to settle out and help return sediment flows to pre-burn levels. Minshall points out that while organisms have evolved to deal with episodic sediment flush events, such as those occurring immediately after a wildfire, they are unable to cope with forestry-induced sedimentation. To these organisms, a forest fire is no big deal, he says. “We get a short few years of sediment runoff, but it’s not a major thing that organisms can’t handle.” But aquatic organisms can’t take unexpected events they haven’t evolved with, such as the presence of fine sediment all year round for extended periods of time. “If we clear-cut, salvage log or put roads in, then the sediment flows tend towards chronic, and it’s a major detriment to organisms,” he says.

Rhodes says that scientists have not identified an upper threshold of logs in streams that is too much for fish. “The more wood, the more fish, all things being equal,” he says. “Lots of wood is a big part of the productivity for streams.” The loss of salmonids in many parts of the West, he says, can be attributed to the absence of wood in streams.

The criteria for healthy ecosystems can’t be easily defined or exhaustively listed. But healthy ecosystems have a full array of processes operating unimpaired, including hydrologic function, soil productivity, carbon sequestering, provision of wildlife habitats and keystone disturbances such as fires, floods, storms and insect outbreaks.

One crucial element present in unmanaged, healthy systems is a significant amount of dead trees and downed wood, Rhodes says. “There is seldom too much dead wood in forests and certainly not in unmanaged ones. However, there is almost always a dearth of it in managed forests.”

Seeing the Forests for the Trees

There’s an old cliché that one can’t see the forest for the trees. It is used to describe people who are so focused on some detail that they fail to see the big picture. Nowhere is this failure to see the forest for the trees more evident than the rush to utilize dead trees for biomass fuel s and/or the presumed need to “thin” forests to reduce so called “dangers” and/or “damage” from wildfire and beetle outbreaks.

Contrary to popular opinion, we probably do not have enough dead trees in our forest ecosystems. And this deficit is a serious problem since dead trees are critical to the long term productivity of forests, and perhaps more important to forest ecosystems than live trees. Dead trees are not a “wasted” resource. It is questionable whether we can we remove substantial quantities of live or dead wood from the forest without serious long term biological impoverishment to forest ecosystems.

An abundance of dead trees, rather than a sign of forest sickness as commonly portrayed, demonstrates that the forest ecosystem is functioning perfectly well. For far too long we have viewed the major agents responsible for creation of substantial qualities of dead trees--beetles and wildfire—as “enemies” of the forest, when in truth; they are the major processes that maintain healthy forest ecosystems.

Recent research points out the multiple ways that dead trees and down wood are critical to the forest. One estimates suggests that 2/3 of all species depend on dead trees/down wood at some point in their lives.

Dead trees are very important for functioning aquatic ecosystems as well. Trees create structure in streams that shapes stream channels, reduces water velocity and erosion, and provides both food and habitat for many aquatic invertebrates. In general the more wood you have in the stream, the more fish, insects, and other aquatic life. Aquatic ecologists generally believe that there is no upper limit for dead wood in streams.

Once a tree falls to the ground and gradually molders back into the soil, it provides home to many small insects and invertebrates that are the lifeblood of the forest, that help recycle and produce nutrients important for present and future forest growth. For instance, there are hundreds of species of ground nesting bees that utilize down trees for their home. These bees are major pollinators of flowers and flowering shrubs in the forest.

Ants are among the most abundant invertebrates in the forest and many live in down trees and snags. Ants play a critical role in the forest, helping to break down wood, aeration of soil with their burrows, and protection of trees against the onslaught of other insects. One study found that ants killed 85% of the tussock moths that attacked Douglas fir and there are many other examples of how ants protect trees from tree predators.

And it’s not just wildlife that depends on dead trees. A recent review of 1200 lichen species found that 10% were only found on dead trees, and many others prefer dead trees as their prime habitat. Lichens, among other things, are important convertors of atmospheric nitrogen into fixed nitrogen important for plant growth.
Even the charcoal that results from wildfires burning up trees is important for soil productivity, helping to increase soil nutrients, water-holding capacity, and as a long-term storage mechanism for carbon.

Most beetle and wildlife events do not kill all the trees. Instead, they create a mosaic of age classes that actually increases biodiversity. Contrary to the popular opinion that beetles “destroy the forest” and fires “sterilize” the soils or create biological deserts, several recent studies have concluded that both beetle killed forests and the burned forests that result remain after stand replacement wildfires have among the highest biodiversity of any habitat type.

Notwithstanding, the fact that much new research suggest that both thinning or biomass removal are often ineffective at slowing or stopping large fires or insect outbreaks because these events are primarily driven by climatic/weather factors rather than fuels, there is the issue of whether the cure is worse than the so-called disease.

Logging, thinning, biomass removal and other forest management introduce all kinds of negative impacts to the forest ecosystem from the spread of weeds to soil compaction to alteration of water flow, disturbance to wildlife, creation of new ORV trails, increases in sedimentation, that all lead to the degradation of the forest ecosystem itself. Most of these negative impacts are ignored or glossed over by proponents of thinning and biomass removal.

In short, current efforts to thwart, and stop beetle outbreaks and wildfires create “unhealthy forests”. In fact, nearly everything that foresters do from thinning forests to suppressing fires degrades and impoverishes the forest ecosystem. Forest “management” is so focused on trees and wood products, that it represents a critical failure to see the forest through the trees.

Wildfires and Dead Trees Needed

Wildfires and Dead Trees Needed

This is a letter to the Register Guard in Eugene, Oregon responding to a recent letter from Mike Dubrasich, a timber industry advocate.


WILDFIRES AND DEAD TREES NEEDED

George Wuerthner


In his January 19th Register Guard guest editorial on forests and fire, Mike Dubrasich, suggests that fire suppression had led to higher fuel loadings, and hence is responsible for the large blazes we have seen around the West in recent years. And he advocates logging as a prescription to "restore" forests to their historic condition. Unfortunately Mr. Dubrasich conflates very different fire regimes into one narrative that inaccurately portrays the causes of recent large blazes as well as the influence that fire suppression may have had on PNW forests.

Only the lowest elevation grasslands, oak savannas and ponderosa pine forests tended to burn frequently and contrary to timber industry rhetoric even these forest occasionally burned in stand replacement fires. Fire suppression may have increased fuels in these forests, but since only a small proportion of our woodlands are of this forest type, the influence of fire suppression is greatly exaggerated.

The bulk of all forest types in the PNW, including most fir, hemlock, spruce, and other mid-higher elevation forests historically burned infrequently and as mixed or high severity stands replacement fires. Because of the naturally long interval between fires--often hundreds of years--fire suppression has had a minimum affect on most forests types since they have not "missed" a fire rotation and there is no unusual fuel buildup.

This is important because the majority of acreage burned annually occurs in higher elevation, longer fire regime kinds of forest types. Large blazes in these forest types cannot be attributed to fire suppression activities, nor are large stand replacement fires "abnormal" or a sign of "unhealthy" forests as timber industry advocates try to portray.

The main factor contributing to large blazes around the West is not fuels, but climatic/weather conditions. The period between the 1940s and 1980s was moister and cooler than previous decades earlier in the century as well as recent decades. This is exactly the same time that people are suggesting fire suppression was effective. But another interpretation is that it was too wet to burn well during that period.

Timber industry proponents try to link fuels with fire, but it is climatic and weather conditions that permit any fuels to burn. If you have extensive drought, coupled with low humidity, high winds, and high temperatures, you can get large blazes—no matter how much or how little fuel you have.The West has been experiencing some of the worst droughts in centuries so it's not surprising that we are seeing large blazes.

The 2002 Biscuit Fire illustrates this finding. Old growth stands and north slopes—the very forest types with the highest fuel loadings and greatest biomass--were the least likely to burn. By contrast younger forests, open savannas of Jeffrey pine and shrub dominated south slopes which had far lower fuel accumulations made up the bulk of acreage charred by the blaze.

Another study found that areas that had been "salvage logged" after the Silver Fire and subsequently reburned in the Biscuit Fire had higher fire severity than unlogged stands, even though these stands obviously had far less biomass (fuel) than unlogged stands.

The explanation is simple—north slopes and old growth forests retained moisture better--and despite the high fuel loads, are more difficult to burn. By contrast, open forests and south slopes exposed to the sun dry out sooner and typically had more "fine" fuels, thus burn better. This is one reason why "thinning" can enhance the chances that a stand will burn because removing trees opens up the forest to higher solar radiation and wind—both of which contribute to fire spread.

A third misconception perpetuated by the timber industry is the idea that dead trees are somehow undesirable and an indicator of "unhealthy" forests. In reality dead trees are the foundation for forest soil productivity. Dead trees are also important for most forest dwelling species—with fully 2/3 of all forest species dependent upon them at some point in their lives. Wildfires, along with insects, are the major agents for producing dead trees and contributors to healthy forests.

Contrary to popular opinion, our managed forests are the ones that are "unhealthy" and "sick". Managed forests typically have less dead trees, and are biologically impoverished and degraded.

The timber industry keeps trying to tell us that all they care about fixing the forests degraded by none other than past forestry practices—and now suggest that we need more logging to fix the problems they created. I am willing to bet if there were no profit in logging our forests, they wouldn't give a hoot about forest health, restoration, wildfires or anything else. It's all a rationalization for exploitation.

Forests have survived for thousands of years with wildfire and insects and they don't need our help to survive or be healthy. I suspect forests live in far more fear of foresters who possess too much hubris, than of any wildfire.