Burning Questions

A couple of years ago I went on a show me tour of a Forest Service Thinning project that was funded under the National Fire Plan (NFP). A group of us, including some forest service employees, a university fire researcher, country commissioners, timber interests, and the like gathered at the Forest Service office. The district ranger explained that we were going to see a fuel reduction project designed to protect the small town where we were standing.  After giving preliminary background on the proposed timber sale, we got into a bunch of Forest Service vehicles and drove out of town. And drove.  And drove. And drove.  Eighteen miles from the town, we got out of the car to look at the thinning project.

Standing among some ponderosa pine that had already been logged, many of them quite sizeable judging by the stumps, the district ranger and other Forest Service employees explained how this thinning project was designed to reduce the spread of fire into the community and eliminate so called “catastrophic fires.” The presumption being that such fires are a result of fire suppression and fuel build up. The solution, proponents of logging argued, is to thin the forests and reduce fuels, hence eliminate large blazes.

After all he and the others finished their presentation, they took questions and comments. The county commissioners said some approving remarks about how it was great the Forest Service was finally getting back into logging. The timber guys were happy—especially since they had retooled their mill to take smaller diameter trees. In general everyone seemed pleased with the proposal.

Then I raised my hand, and asked why they were cutting trees here, when the town was eighteen miles away. Shouldn’t they be thinning there? There was a silence. The district ranger, a reasonably intelligent and informed guy, kicked at the dust. He started to smile a bit and almost seemed relieved that I had posed the obvious question.
Finally he spoke and admitted yes they should probably be thinning next to the town if the goal was to protect the town but he indicated that he was under pressure just to get the cut out and the timber volume was greater here. He also admitted to us under further questioning that the thinned forests–under reduced competition resulting from the thinning efforts– would likely grow back quickly, and largely negate much of the supposed value of fuel reduction.
He went on to explain that long before they had completed the full project (tens of thousands of acres) they would have to come back and log the original acreage to maintain its effectiveness as a fuel reduction. In truth, he didn’t see how they were going to implement the project successfully.

I pointed to the surrounding pines which appeared to be similar size and age. Oh, yes, I was told by the university fire researcher that was because in 1860 or so there had been a large stand replacement fire in the basin and most of the trees had regrown from that event.

I said that was interesting since 1860 was before any white settlement in the area. In other words before  there was any logging, grazing or fire suppression to create “unnatural” fuel build ups, so how could the basin full of ponderosa pine burn up in a stand replacement blaze if fuel build up is what creates large stand replacements fires? No response. The idea had apparently not occurred to anyone before.  But the admission demonstrated clearly to me that the generalization that fire suppression is responsible for most large blazes may be overstated.

Now a new review study that looked at implementation of the Forest Health plan in the West by Tania Schoennagel and colleagues from the University of Colorado, Colorado State and University of Montana lends credence to ideas I and other critics have been suggesting for years.

Schoennagel et al. reviewed 44,000 fuel treatments done across the West under the rubric of the National Fire Plan (NFP). Despite the fact  that the plan directs that treatments should be done where they would be most effective at reducing fire hazards to homes and communities, their analysis showed that only 3% of all thinning projects were in the so called “Wildlands Urban Interface” (WUI). Most were like the thinning project I visited in Oregon—miles from any community.
They also noted that the majority of land (83%) that could be treated within the WUI lies on private property.  In other words, even if thinning did work to reduce fire intensity and spread, the focus on federal lands does little to effectively protect homes and communities.  Many studies have demonstrated that the most cost effective means of reducing fire hazard to homes and towns is to reduce the flammability of individual homes, not by logging the forests.

A further problem touched on by the review is a failure to acknowledge by thinning proponents that climate plays a major role in driving large fires. If you have severe drought, low humidity and high winds—especially high winds—nothing can effectively stop a blaze.

Basically you have to wait until the weather conditions change. In the hierarchy of factors that affects fire spread, climate trumps fuels.
By contrast, if the weather/climate conditions are not favorable for fire spread, it doesn’t matter how much fuel you have, you won’t get a large blaze. There are tons of fuels per acre in West Coast rainforests, yet these forests seldom burn because they never dry out sufficiently for a blaze to grow into a large fire, even if one starts by lightning or from people.  Yet there is more fuel in those forests per acre than you would find in a hundred acres of a drier forest.

Similarly, many high elevation forests in the West—think lodgepole pine in Yellowstone—are typically too wet to burn in most years. That is why fires in such forest types are infrequent, but when they do occur, they tend to be large blazes that kill many of the trees.

The vast majority of acreage burnt in recent years by large fires isn’t in the low elevation forests that may have been influenced by fire suppression and fuel-build up. They are occurring in forests that normally burn in mixed intensity to severe intensity stand replacement fires when conditions are right for such blazes. Considering that we have experienced extraordinary drought in many parts of the West, the fact that we are seeing large fires may not be “abnormal”.  Large stand replacement fires are exactly what one would expect in such forest types under severe climatic/weather conditions.

And these forests types—including higher elevation forests of subalpine fir, lodgepole pine, as well as moister lower elevation forests of Grand fir, western red cedar, western larch and other species—make up the majority of all forest types in much of the Northwest and Northern Rockies. For instance, one study found that 96% of the forest types in the Northern Rockies of Idaho and Montana are either low elevation moist montane forests or higher elevation forest types. These forest types have long intervals between fires and tend to burn only when climatic conditions are favorable for fire spread. As a result the fuel loading in the majority of these forest acres are not likely to have been altered due to fire suppression.

But new research from around the West is even questioning the old that generalization that lower elevation dry montane forests were always characterized by low intensity frequent blazes. This idea, sometimes called the “Southwest Ponderosa Pine Model”, has come to dominate the common perception about all forest types and fire behavior.

In the Southwest ponderosa pine forests, there is good evidence to suggest that wildfire was frequent and tended to maintain open forest stands dominated by widely spaced large fire resistant pines. With fire suppression, logging, and livestock grazing, these forests are today stocked more densely, and some suggest, more prone to stand replacement blazes.

People around the West apply this Southwest model to all forest types, even remote high elevation forests where few fires were successfully suppressed, and where natural fire intervals are much longer—meaning that fire suppression could not have contributed to significant alternation in fuel loads.

However, muddling the waters further even on the Southwest ponderosa pine model is that researchers are finding is that in some parts of the country including Colorado, Idaho, Montana, Washington, Oregon, and elsewhere that stand replacement fires may be “natural” even in lower elevation dry montane forests dominated by ponderosa pine and Douglas fir. In other words, stand replacement blazes even in these forests are not out of the ordinary.

This research suggests that under some climatic conditions, even these forests will burn and burn well like the ponderosa pine filled basin I had visited on the FS tour that had burned in a stand replacement fire in 1860, long before fire suppression could have had an influence.  It is now acknowledged that it’s quite possible for forests dominated by low intensity blazes may occasionally burn under severe weather conditions as stand replacement fires as well.

If climate overrides fuels, than fuel reductions are not likely to have a significant impact at stopping the prevalence of large fires.  And this appears to be borne out in how fires have burned throughout the West.  The actual effectiveness of logging forests to reduce fuels and thus fire spread and intensity has had mixed results. There appears to be some places where fuel reductions appear to have reduced fire spread and fire intensity. However, there are plenty of examples of blazes around the West where fires raced through heavily thinned and logged stands, even clearcuts.

In my informal review of these fires, it appears that thinning may work under less than severe climate/weather conditions, but fails when climate/weather conspires to support large blazes. In other words, even if thinning “appears” to work under less severe conditions, it typically fails under severe weather/climate conditions of extended drought and high winds—which is one factor why there are “mixed” results reported on the effectiveness of thinning in the scientific literature.

Other factors contributing to mixed findings of thinning effectiveness include no precise definition of what constitutes thinning. How many trees per acre do you remove, and what size tree affects fire and fuels. Thinning may actually exacerbate fire spread by opening the forest to more heat and wind.

Plus thinning can increase small diameter fuels which are the major factor in fire spread, so most research suggests that thinning effectiveness is greatly enhanced if the area is burned after logging to remove fine fuels. But most thinning operations do not use pre-burning to reduce fine fuels after logging operations are completed.

The time since a forest was thinned is yet another factor.  The effectiveness of a thinning on fuel loading rapidly declines, which is why they cannot be thought of as a one-time treatment. Thinning reduces competition and opens up a forest canopy permitting rapid growth of understory shrubs and trees—which are the major components of fire spread.

Depending on the vegetation, studies have shown that within 10-20 years, fuel loading can often return to pre-thinning levels. Thus any thinning done to supposedly reduce fire hazards must be thought of as an on-going treatment that requires continual maintenance.  Doing such maintenance over millions of acres is impossible. That is another reason to focus thinning on the WUI and not miles from towns.

Even if thinning did work to a degree, that doesn’t mean it’s the best solution to the perceived problem. Again circling back to the Schoennagel review, much of the “problem” isn’t large fires—which have always occurred in the West under severe climatic conditions—rather it is the result of expansion of new housing into the wildlands.

According to their review the Wildlands Urban Interface increased 61% between 1970 and 2000. This is primarily a result of inadequate or none-existent zoning. Had county commissioners, most of whom are so called “private property advocates”, implemented strong zoning to concentrate housing in appropriate less fire prone areas, much of the hand wringing over fires could be avoided. Indeed, one could suggest that anti zoning zealots—often the same people who advocate logging—are the source of the fire hazard problem.

Beyond zoning, reducing home flammability has been shown to be very effective at reducing housing losses to fire. Over the past five years, I have visited many fires where homes were incinerated. In the majority of the homes I have seen, the fire did not actually reach the house. I have striking photos of burned out basements with green trees surrounding the home.

In almost all cases, what has occurred is a spark carried by the wind lands on some house with a wooden shake roof covered with pine needles and the house burns to the ground. Installation of a metal roof, in many cases, is all that is needed to reduce home flammability significantly. Even subsidizing the replacement of wooden roofs with metal in vulnerable homes may be far less expensive than fighting fires and wasting tax dollars on money losing timber sales.

Finally, and I always circle back to this last factor, logging is not benign. There is no such thing as a “good” logging operation. There are few truly “sustainable” logging operations. These are clever ruses to deceive the public. Logging always has significant ecological impacts and we should always enunciate them. Whether the benefits that may accuse from logging in terms of wood products, and even in some cases, a reduction in fire hazard are worth the true ecological costs is often difficult to determine because few reviews fully articulate the real costs.

My observations of so called fire reductions projects observed throughout the West is that most are nothing more than an excuse to log. The NFP is a Trojan Horse. Using fear of fire, and ignorance about fire ecology and what conditions support large blazes, logging proponents have so far been successful at duping the public, many politicians, and even some environmental organizations into supporting inappropriate logging proposals.

I personally would feel a lot better about any logging proposal if the FS and other supporters just came out and said, the reason we are logging is to get some timber out of the woods. Then we could have an honest debate about whether this is really in the public interest. Instead, far too many timber sales are wrapped up in the flag of fuel reductions that are neither effective nor in appropriate locations. The Schoennagel et al. review just gives further credence to this perspective. The review can be found at www.pnas.org

GEORGE WUERTHNER is editor of Wildfire: a Century of Failed Forest Policy.

George Wuerthner has published 36 books including Wildfire: A Century of Failed Forest Policy