Without Preliminary Thinning, Fires Are Deadly to Old-Growth

The following article appeared last week in the Payson Roundup. [Note: Payson is located approximately ninety minutes North of Phoenix, AZ in the heart of Arizona's Rim Country. Ninety-seven percent of the land around Payson is under the jurisdiction of the United States Forest Service (Payson is surrounded by the Tonto National Forest) or by tribal governments.]

The article was written by Pete Aleshire, Southwestern journalist, editor, and author. [Note: As a senior lecturer at Arizona State University's West Campus since 1992, Mr. Aleshire has taught journalism, magazine writing, creative nonfiction and other courses. He has published four history books about Arizona's Apache Wars -- "Reaping the Whirlwind," "Cochise," "Warrior Woman" and "The Fox and the Whirlwind." His articles have been published in Phoenix Magazine, Geo, Reader's Digest, Cerca, Arizona Highways, and other magazines.]

The article is about the work of Dr. W. Wallace Covington, Regents’ Professor of Forest Ecology at Northern Arizona University and Director of the Ecological Restoration Institute [here]. Dr. Covington been a professor teaching and researching fire ecology and restoration management at NAU since 1975 and is widely recognized as a founder and world-class expert in forest restoration.

An earlier essay about Dr. Covington, Friendly Fire by Stephen J. Pyne, may be found in the W.I.S.E. Colloquium: Restoration Forestry [here]. Dr. Covington’s 2002 testimony to Congress regarding the Wildland Firefighting and National Fire Plan is also posted in that Colloquium [here].

Mr. Aleshire’s article (emphases in bold by SOSF):


Saving the Pine Forest

Wally Covington has shaped the debate and befuddled critics with woodsy charm and the tenacity of a badger

By Pete Aleshire, The Payson Roundup, August 7, 2009 [here]

Wally Covington, who has spent a quarter century reshaping the debate about forest management, leaned forward excitedly across the boundary between his biggest disappointment and his dearest hope.

On one hand, lush grass and scattered flowers swayed in the dappled sunlight in an open forest dominated by widely spaced, ponderosa pines.

On the other side of a wire fence huddled a dark, thick forest, with the smattering of grand old trees besieged by tangles of spindly saplings — the ground covered by pine needles rather than grass.

The contrast between those two patches of forest underlies his unsettling conclusion that the forests of the Southwest sway at the edge of ecological disaster, which can only be averted by a politically unlikely reinvention of the timber industry to thin millions of acres as a prelude to restoring fire to its rightful role.

The gangling, former medical student and current professor of forestry at Northern Arizona University has spent the last quarter century studying these two patches of forest just outside Flagstaff. His findings have spurred controversy and dominated a high-stakes debate about the future of the ponderosa pine forests of the Southwest.

He has alternatively lambasted Forest Service land management practices, indicted unrestricted cattle grazing and outraged environmentalists — all of it by doggedly pursuing the evidence on the ground.

Tall as a lodgepole pine with big hands, big ideas and the persistence of a badger, Covington has argued tenaciously that the only way to save the world’s largest ponderosa pine forest is to reduce densities from the current 800 to 1,500 trees per acre to the 25 to 50 trees per acre densities of the pre-settlement forest. Fire alone can’t do that, thanks to the degraded condition of the forest today, he says.

If he’s right, then the current Forest Service emphasis on letting low-intensity fires like the recent Milk Point Fire simply burn will likely provide less protection for Rim communities than foresters and residents might hope. Renewed fires without preliminary thinning might not only leave the problematic small trees and debris intact, but could preferentially kill the big trees the forest needs to regain health, concluded Covington, as a result of a 25-year experiment with side-by-side patches of forest.

A child of the ’60s born in 1947, he was raised in Oklahoma by a father who was a forester, prizefighter, radio announcer and barnstorming pilot. His father imbued a hard-headed, reverence for the woods, in the course of years of hunting, fishing and camping — buttressed by readings from Aldo Leopold’s San County Almanac.

After his father died and his mother survived a struggle with cancer, Covington headed off to medical school. But he found the emotional impact of dealing with dying cancer patients too taxing, so he got a master’s degree in biology at the University of New Mexico, then a degree in forestry from Yale.

He has been working tenaciously to understand the unhinged ecosystems of the drought-adapted ponderosa pine forest ever since, with a childlike enthusiasm for discovery, a low-key, woodsy charm, an unflappable sense of proportion and a rare ability to think on the scale of a 300-year-old tree.

Covington’s findings indicted a century of wrong-headed Forest Service management, especially fire suppression, cattle grazing, and to a lesser extent, clear-cut logging. So environmentalists pushing for a return to a healthy, natural forest initially embraced his findings.

But as the data accumulated — especially along this vital fence boundary in the oldest experimental forest in the Southwest — Covington was forced to reluctantly give up the idea that a careful return of fire without preliminary thinning could restore forest health.

Ironically, after having played a vital role in convincing the Forest Service to abandon a simple-minded effort to stamp out all forest fires, Covington now finds himself in an uncomfortable no-man’s-land between advocates of the rapid, widespread return of fire as a management tool and environmentalists advocating a hands-off approach.

The shift has made him the chief proponent for a re-invented timber industry as the only way to prevent the inevitable return of fire from perhaps eliminating ponderosa pines across millions of acres — endangering a host of forest communities in the process.

Covington’s prescription combines hand-thinning followed by restoration of a natural fire regime. Termed the “Flagstaff Model,” that prescription is now being applied in a wide buffer zone around Flagstaff and Rim communities like Payson, Pine and Strawberry. Covington also got research grants from the federal government to test his approach to forest restoration on a huge expanse of dark, crowded forest on Mount Trumbell in the Arizona Strip.

His prescription has proven controversial. The drastic reduction in tree densities initially leaves a treated forest looking devastated. Moreover, the logic of his research leads to the conclusion that only a restored timber industry that can make money on millions of small diameter trees can save the forest.

His argument rests heavily on what you see when standing on this boundary between two differently managed patches of experimental forest.

His studies in several experimental forests near Flagstaff have shown that the current forest bears little resemblance to the open, sunny, grassy forest that existed before the arrival of Europeans in the area some 200 years ago. In the Gus Pearson Natural Area, established in 1908, photographs and the meticulous plotting of every old-growth tree, stump and scrap of wood showed a dramatic increase in densities — from 22 trees per acre to more than 1,200. Covington blamed that increase on both fire suppression and cattle grazing, since the cattle removed the grass that could carry the periodic, low-intensity ground fires to which the forest had adapted.

So the researchers decided to “treat” the forest in different ways and compare the results, starting in 1992.

One patch, they left alone as a control sample.

In an adjoining patch, they cut down enough trees to restore densities to 1876 levels, then left it alone to study the result. That involved leaving more than 23 trees per acre, since they left several small trees for each old-growth stump they located, to ensure one would live long enough to replace the missing giant.

In the third patch, they thinned trees, then set ground fires every four or five years to burn off brush, leaves on the ground and returning seedlings. In that treatment, crews also raked away the thick layer of needles and debris that had accumulated at the base of all the big trees during the decades of fire suppression.

The results were dramatic. The remaining trees immediately increased their growth rate, up to 55 percent in most cases. The gains proved especially dramatic during the drought. The leaves of the trees had significantly more nitrogen and tougher foliage, with great resin flow. That resin flow dramatically increased the tree’s resistance to bark beetles, which have killed millions of pine in recent years.

The thinned forests — especially the patch with regular fires — produced six times as much grass, which nearly doubled the number of animal and insect species present — rising from 37 to 66.

Covington then applied that prescription on a wider scale at another, larger experimental forest nearby.

Here, he once again meticulously reconstructed that vanished, old-growth forest. Then his restoration crews removed most of the existing trees, even large trees that were clustered more tightly than the trees of that old-growth forest.

Criticism poured in when people got a look at the severity of the thinning. Some environmental groups even posted photos of the seemingly denuded landscape on Web sites to decry Covington’s approach.

But year by year, the forest recovered, with lush grass and flowers.

Now, that small extent of forest looks like a restoration postcard, in stark contrast to the dark, crowded, huddled forests that surround it.

The restoration of that experimental forest stands as Covington’s dearest hope, since it provides a model for the restoration of an endangered forest he loves.

However, his greatest disappointment still reproaches him from the other side of the fence, a rebuff to his once fiercely-held hope that the forest could be saved with the simple reintroduction of fire.

In that adjoining patch, the Forest Service tried its hand at using fire alone to restore ecological balance. The Forest Service for some 20 years has regularly set fire to that experimental patch of woods, timing the fires for the cool spring and fall conditions that would keep the flames from getting out of control. Foresters hoped the fires would creep through and burn off the brush and saplings, leaving the big trees intact.

Oddly enough, just the opposite happened. The fires often wandered through without consuming the downed logs or even many of the saplings. However, the heat did settle into the mounds of leaves and needles built up over decades around the bases of the big trees.

The intense heat at ground level girdled the trees, cutting off the flow of nutrients and moisture just under the bark up to the leaves above. As a result, the ground fires that burned through without first removing the debris from the base of the big trees left a thick tangle of forest — but preferentially killed the bigger trees, said Covington.

“That was a big disappointment,” he said, “we were really hoping that would work.”

Obviously, it would have made the job of restoring the forest far less costly.

In the fire season just past, the Forest Service has embraced the idea of letting fires burn, including the big fire on Milk Ranch Point.

Burns without preliminary thinning only cost a couple hundred dollars per acre, since crews must simply contain the fire and keep it from spreading toward structures. By contrast, it costs about $1,000 per acre to hand thin the forest, pile up the debris, then burn the slash pile. Forest Service crews have done just that on thousands of acres surrounding Rim communities, but obviously can’t afford to take that approach on the millions of acres of unhealthy forest.

All of which brought Covington to the conclusion that the only remaining hope is to develop a timber industry that can do the thinning work at little or no cost to taxpayers.


Note: I hope the message got through. Overgrown forests must be prepared to receive fire, by thinning and other fuel treatments, or the inevitable fires will kill all the trees.

It is sheer sophistry born of inexperience and ignorance to assume that wildfires “thin” forests, that Mother Nature’s fires preferentially burn small trees and leave large ones. That is NOT what happens in real life.

Forest restoration requires active, hands-on, scientifically designed, ecologically sensitive treatments to be successful. Experts including Dr. Covington understand this by virtue of long experience, experiment, and observation.

12 Aug 2009, 7:00pm
by bear bait

Covington debunks that BS myth about “benign fire.” I have seen the bark duff four feet deep around the base of old growth doug fir. Not those Congressional, urban old growth 22″ dbh and larger, but around the base of real old growth, the 70″ dbh trees with the dished bark and the annual detritus load increasing faster than decay can consume it.

Early blacksmiths used old growth doug fir bark instead of coal to heat metal. That same bark, piled feet deep around the bole of forest giants, will not only catch fire but will hold fire for months and girdle the old timer trees like an 074 Stihl with a four foot bar. There is no longer a possibility that fire can be benign and wonderful on many of our forests. That lie has been debunked, but still persists in the urban legends of townie forestry.

If you ever figure out a way to change the course of that ship, you will save forests. Until then, I guess we just make sure the cones wear condoms and friendly fire doesn’t take too many. Pshaw!!

13 Aug 2009, 1:48pm
by Larry H.

A new fire has broken out in the Santa Cruz mountains of California. Since yesterday afternoon, the fire has grown by leaps and bounds, in brushy, unmanaged old growth stands. The fire behavior has been quite extreme, with 300 foot flames engulfing thick pines and Douglas fir. There is also a knobcone pine component that is surely adding to this dangerous situation.

This morning the fire was 1000 acres and it now stands at 2300 acres, with 2400 people under an evacuation order. Increased winds are expected today and tomorrow, with an offshore low pressure system activating the ocean breezes.

It’s gonna get UGLY!!

Note: see the Lockheed Fire at W.I.S.E. Fire Tracking [here]

13 Aug 2009, 8:58pm
by Bob Z.

I was disappointed to see that Wally’s prescription costs a thousand dollars an acre and prepares the ground for “natural” fire.

Precommercial thinning pine is cheap. Hand-piling and burning is likely where a lot of the cost comes in. Maybe raking fuels around the basal areas of larger trees.

If the slash piles could be mechanically raked (of course they can), chipped, and sold — even with a subsidy — that would save the money spent on hand-piling and burning, and generate an income, no matter how modest. That means regular jobs that produce taxes, rather than depend on them.

If a forester would design a thinning sale to make a profit (that’s what a lot of them are paid to do), there would be no cost and more jobs.

If people are “natural” and are allowed to set broadcast burns so that needles and woody debris don’t build up, the fires are cheap, local jobs are created, and wildfire is averted. Leiberg estimated that Indians in SW Oregon burned forestlands when fuels built up to “1/2 to 3/4 inches deep.” That is, every few years, when there was barely enough fuel to carry a flame.

So, in my estimation, Covington is getting there, but needs to learn two more things: 1) how to design a thinning sale that makes money (or costs a lot less than $1000/acre and doesn’t involve burning energy- or other wood product-producing slash piles), and 2) how to plan broadcast burns thousands of acres in size that only cost a few dollars an acre to perform.

In sum, a combination of American Indian pine forest management techniques combined with modern economic realities will reduce wildfires, produce jobs, and help create, restore, and maintain millions of acres of western US pine forests. Good to look at, safe to visit, and a nice place to live for working people and wildlife.

13 Aug 2009, 9:25pm
by Mike

Bob, you may not be familiar with NAZ pine forests. They are pretty scrubby. Even the old-growth would barely make merch around here. There are upwards of 1,500 stems per acre, most of them less than 20 feet tall. In Oregon we might call that pine brush.

Those forests cannot be gently burned without PCT. There is too much fuel and the leave trees get easily girdled and killed, even if the fire doesn’t crown. The Kaibab NF does a lot of cheap, no-prep Let It Burn across multi-thousands of acres, but with disastrous after-effects. Their creeping ground fires are easy to control, but they kill the biggest trees.

It is unreasonable to use AZ forests to estimate the cost/benefits of restoration forestry, because they have the highest costs and the least returns. The same treatments in Oregon forests are money makers, because our trees are much larger.

The Indians did not do PCT. They just burned every year or two. Grass/brush resulted, and trees reoccupied the sites very slowly — perhaps one successful stem per acre every 20 years. It took 200 years of frequent burning to develop a savanna with 10 trees per acre. Eventually oak and pine savannas contained some trees of definite value, and those trees may have received special care and protection. But there were not many of those across broad landscapes.

We should not attempt to replicate exactly those ancient methods. It is better to clean out the excess fuels mechanically and prepare the open forests to receive fire. That way we can speed up the process and have healthy savanna/woodlands in just a few years, not 200+.

13 Aug 2009, 9:53pm
by Bob Z.


Not talking about replicating those “exact processes” — only the regular burning. Certainly, there was no need (or even opportunity) for Indians to practice PCT. That is a modern practice needed to mitigate modern conditions.

The scrubby, submerchantable pine condition is an excellent point of which I was unaware. Still — $1000 an ACRE? I’m sure that stuff has some value as fuel, paper, or chipboard — pellets, chips, briquets — something.

And where are the nearest merchantable stands? When my crews used to do planting and PCT projects, our units were often 100 or more miles from one another. People in my line of work often had crews operating on USFS lands in two or three different states at a time. Gas is cheap (sort of), and we have an excellent highway system.

Just saying that millions of acres need treatment, Americans need energy and jobs, and there’s got to be ways other than outlays of massive amounts of tax monies and dependency on undependable and largely unpredictable lightning strikes to get the job done. Faster, better, and cheaper.

14 Aug 2009, 7:20am
by Larry H.

We will need to use every tool in the forester’s toolbox to deal with this ongoing disaster. Since the eco’s are continuing to punish us for what foresters did in the last millennium, they simply will not trust foresters to make those decisions on which tool to use. They’d like to use the least common denominator in order to deal with this situation that they have begrudgingly accepted as “important”. That will mean applying a completely inadequate blanket treatment to every western forest. My guess would be that they will accept a thinning of pole-sized trees underneath the rest of the forest, thinking that will “fix” the problems of millions of acres of dead and dying trees.

14 Aug 2009, 9:39am
by Tim B.

Actually Bob, the thousand $/ac. struck me as being pretty cheap, at least for around here. As Mike pointed out, he’s talking about over 1000 stems per acre; the piling labor alone around here would be at least half that amount. Yes, that material has value but it is very low. If the acreage being treated is more than a few tens of miles away from a processing facility the haul costs alone will easily exceed that value, and if the ground is flat enough to allow the use of machinery to transport it to the road there is the chance of there being cultural resources that could preclude the use of ground-based equipment. I remember a few years back some State economist ragging on the FS because they had not been proactive enough in looking into biomass extraction. So he did his own analysis and determined this type of non-lumber forest biomass does has no value unless right next door to the biogeneration plant. This is indeed a real problem that’s been created by letting prescribed fire go for 100+ years and as best I can see there is no real good and elegant (or cheap) solution. It costs a lot to suppress fires these days and it costs a lot to restore the forests after 100 years of growth. Maybe we need to starting thinking big; resurrect the CCC or something like that.

14 Aug 2009, 10:05am
by Mike

That’s why it is important to think in terms of the opportunity cost-plus-losses of catastrophic fire. Including damage prevention and mitigation in the calculation shows that the economic utility of restoration is positive.

In addition, the post-restoration, open and park-like forest provides enhanced recreation, enhanced scenic beauty, and quite often enhanced so-called “secondary” forest products. Huckleberry fields and beargrass meadows are heritage vegetation types that should be restored, and they produce valuable commodities. In fact, they outperform timber production in terms of present-net-value of the future income stream because huckleberries and beargrass are annual crops, whereas timber may be harvested only once every 50 to 80 years (off any given acre).

Avoiding catastrophic resource damage and providing enhanced production of commodities and non-commodities are two ways in which forest restoration pays for itself many times over.

14 Aug 2009, 10:19am
by Larry H.

I saw an article about a portable bio-char unit being demonstrated in Oregon that could help make PCT projects more cost effective.


Another tool for the forester’s toolbox! Unfortunately, there now seems to be a kneejerk reaction against any kind of biomass-type activity, right now. The people in power continue to resist any and all forestry projects. I guess that until they they smell smoke in Washington DC, they will continue to claim there’s no problem in our forests. (Amazing how people can somehow ignore MILLIONS of acres of dead and dying trees!)

14 Aug 2009, 3:24pm
by Mary

Last year I attended a presentation about local energy production by gassification of biomass producing fuel used to generate electricity. The two gentlemen presenting had done extensive research and determined that rural/national forest in central-eastern Arizona and central- western New Mexico could fuel one of these biomass plants every 50 miles along our few main highways.

The plant would be fueled basically by the slashy biomass removal necessary in the process of returning to and keeping the forest in a healthy state. This is only 25 miles transport. Their figures determined that this would be a sustainable situation between continuous electrical production and the production of more slash for thinning at 50 miles between each low profile plant.

I have not heard of this again. These retired gentlemen apparently put all this together with an altruistic desire to do something good for their fellow man here. I had the feeling at the time that this would not go over big with the “rewilder” types here working 24/7.

These “rewilder” do-baders are almost to a person from somewhere else, they run for mayor and city councils, infiltrate the FS and put on Prescott College recruitment events to get our towns and people off their targeted landscape (slated by them for death by catastrophic fire).

The latest draft of the new Forest Plan, in process in the area, shows proposals on maps for 36 new wilderness areas checker-boarding the area most often showing additional “possible wilderness” and “other possible wilderness” surrounding. These people seem to be more or less writing the plan. In my estimation this misguided attempt at a people-less landscape here is destructive of all forest values. Sorry about drifting off topic.

Reply: Mary, you right on topic and correct in your assessment of the situation.



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