Study: Post-fire logging can reduce fuels for up to 40 years

Salvage logging has been a topic of some discussion here. This study validates what is, in my opinion, common knowledge.

 

U.S. Forest Service | Pacific Northwest Research Station
News & Information

Contact: David W. Peterson, (509) 664-1727, davepeterson@fs.fed.us

Media assistance: Yasmeen Sands, (503) 808-2137, ysands@fs.fed.us

 

Post-fire logging can reduce fuels for up to 40 years in regenerating forests, new study finds

Woody fuels reduced even when fuel reduction was not primary management objective

WENATCHEE, Wash. March 11, 2015. Harvesting fire-killed trees is an effective way to reduce woody fuels for up to four decades following wildfire in dry coniferous forests, a U.S. Forest Service study has found.

The retrospective analysis, among the first to measure the long-term effects of post-fire logging on forest fuels, is published in the journal Forest Ecology and Management.

“Large wildfires can leave behind thousands of acres of fire-killed trees that eventually become fuel for future fires. In the past, post-fire logging has been conducted primarily to recover economic value from those fire-killed trees,” said David W. Peterson, a Wenatchee-based research ecologist with the Pacific Northwest Research Station who led the study.

The study shows that post-fire logging also provides a tangible long-term fuel reduction benefit, giving forest managers another tool for managing woody fuels in dry forest landscapes.

“In comparing logged and unlogged stands, we found that logged stands had higher fuels than unlogged stands, on average, during the first five years after fire and logging, but then had lower fuels from seven to forty years after fire, with the greatest differences being found for large-diameter woody fuels,” Peterson said. “This study provides a sound scientific basis for forest managers to consider fuels management goals along with recovery of economic value and wildlife habitat concerns when deciding when and where to propose post-fire logging.”

The researchers’ analysis revealed that, in unlogged stands, surface woody fuel levels were low shortly after wildfire, peaked 10 to 20 years after wildfire, and then declined gradually out to 39 years past the wildfire. In logged stands, small- and medium-diameter fuels reached their highest levels shortly after the wildfire and then declined in subsequent years, but larger-diameter fuels changed relatively little over the entire time range.

Peterson and his co-authors sampled woody fuels on 255 coniferous forest stands that were killed by wildfires in eastern Washington and Oregon—the region’s most fire-prone areas—between 1970 and 2007. Their sample included 96 stands that were logged after wildfire and 159 that were not, an approach that allowed the researchers to test the effects of post-fire logging on forest fuels. The researchers accounted for pre-fire stand differences by measuring standing and fallen dead trees and stumps in each stand. They did not consider the effects of post-fire logging on sediment, wildlife habitat, or aesthetics.

 

The Pacific Northwest Research Station—headquartered in Portland, Ore.—generates and communicates scientific knowledge that helps people make informed choices about natural resources and the environment. The station has 11 laboratories and centers located in Alaska, Washington, and Oregon and about 300 employees. Learn more online at http://www.fs.fed.us/pnw.

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12 Comments

    • Nor did they study the no-harvest effects on sediment, wildlife habitat, or aesthetics. If done properly, a post-harvest logging operation can include significant anti-erosion measures. In most cases, many dead trees are left, even in harvest units, and they offer lots of habitat. Aesthetics? Well, a salvaged stand may not be pretty to some folks, but others would says that a salvaged stand that is replanted with trees looks better a few years or decades later than a brushfield.

    • Surely, you must know that every Forest Service salvage project has site-specific snag requirements. Sometimes it is even a two-tiered requirement, for retaining two different sizes of snags, per acre. Of course, opponents do not want to talk about all the acres burned that aren’t being salvaged, too. Yes, if you are talking about private salvage logging on private lands, I’m with you on that. Especially when the land ownership is checkerboarded.

      • In my experience, implementation of the snag retention policy is problematic. (Skinny little snags left when the big trees are cut. Or poorly dispersed snags.)

        And you are right: post-fire logging on USFS land is worlds different than private lands.

        • In my experience, the diameter has always been clearly defined. I’ve even seen where the “largest and straightest” trees were left for wildlife. I also forgot to mention the clumps of snags left, along with the individual trees per acre requirements. Of course, there are also the snags that are contained within streamcourse protections, as well as the incinerated (but still “protected”) core habitats. There are no lack of snags, if you look at the overall burned areas. There aren’t enough blackbacked woodpeckers in all of California to utilize the snags in the Rim Fire.

          To me, the success of a salvage project might be measured in the utilization of the smallest diameter trees of merchantable size. This is the area of economics that the delay tactics of the preservationists affect the most. Ironically, I have to applaud some of those same folks who have made a concession that “snag thinning” is fine with them, in certain situations. Make no mistake that this is an important step in reaching more consensus, in some key areas of forest management policy.

          I have always thought that compromises were the inevitable result of increased education, collaboration and consensus.

  1. My apologies; I am used to more rowdy crowds.

    Here are my concerns with the study: (1) It is essentially a tautology–removing woody biomass removes fuel; (2) the study assumes that this removal will reduce future fire behavior, contrary to other studies (e.g., McGinnis et al. 2010); (3) the study doesn’t address the impact on fire behavior from conifer plantation and herbicide spraying (a common occurrence).

    Lastly, I find it hard to believe a study produced by the Forest Service which has a financial interest in post-fire logging.

    • There are MULTIPLE benefits to salvage logging, done right. There aren’t many impacts, and those are mitigated. Modern salvage projects meet multiple objectives. Replanting unsalvaged fires does not work when the fire return interval is 20-40 years, like here in the Sierra Nevada. Then you can add in the increased human use, and their unintended (and intended) wildfires. We can plan for firestorms, or not. Since the last glaciation, our landscapes have been dominated by humans, in many areas. Here in California, wherever you see huge pines, you can be sure that the expert California Indians “managed” those lands, through burning practices. Today’s forests won’t magically turn into those forests of pre-European times. Right now, there is no thinning and there will be very little burning, as well. Politics has prescribed this “Whatever Happens” situation, supported by preservationist groups.

      The Rim Fire is a perfect example of an all-or-nothing scenario. You should not replant if you cannot reduce the fuels, or use herbicides on the fire-adapted bearclover. If pines don’t get re-established immediately, they won’t grow in the shade of all the bearclover, ceanothus and manzanita. Remember, the Rim Fire salvage plan only included 30,000 acres, including huge 40 year old plantations and roadside hazard tree projects.

      I have seen some interesting post-fire plantation thinning projects, complete with wildlife islands. Such areas require proper management as the trees continue to grow.

  2. Post fire salvage on private ground may not look so good at first, but in a few years it will be green with new growth of young trees. The fire killed trees will be typically be harvested while they still have economic value.
    When seeing the amount of fire kill acreage on public ground (and I have just seen a small amount of it) that is just being left to recover naturally it makes my heart sink. Some areas in the higher mountains seem to be recovering not at all or at least not growing any trees.
    I still think that the fire policy of the Forest Service that has been implemented since the Northwest Forest Plan have lead to some the largest wholesale destruction of our old growth forests ever.
    (and at great expense to public)
    An aggressive plan of post fire salvage by the Forest Service will usually harvest less that 2% of the burnt timber and after they have jump through all the hoops needed to sell fire salvage only the bigger trees will have economic value.
    Post fire salvage is a legitimate way to promote economic activity in our rural communities. It provides jobs. It provides resource. It maintains our ability to access and manage our public forests.
    In MHO it is a failure on the part of our society, to first, not aggressively try to stop these fires when they first start and preserve our forests. Secondly I think is it incredibly wasteful not to make something out some these trees, that represent some of the most valuable natural resource in the world, that are now dead.
    I have seen where post fire salvage can take place with no harm to environment, without causing erosion, or harming wildlife and that these forests can recover just as well if not better than those left to “whatever happens”.
    As far as aesthetics go, logging operations never look great at first, but I think looking at whole watersheds of dead trees is not exactly inspiring either. Some roadside salvage projects would look better if units were not bound by what trees might reach the roads but with boundaries that are mixed up and make sense for harvesting.
    The other day looking over at the Biscuit Fire some of the mountains that were once green and lush with forests looked brown and dry like some desert landscape waiting for the next fire.

  3. This is a very misleading press release which the FS should be embarrassed to put their name on.

    It says “… with the greatest differences being found for large-diameter woody fuels,”

    A better word for “large diameter fuels” is HABITAT.

    Fine fuels are a fire hazard and they are increased by salvage logging (which moves fine fuels from the canopy to the ground where they are more available for combustion). Fine fuels are also increased by replanting (which established dense conifer with abundant fine fuels close to the ground).

    Large wood is not a significant fuel hazard, but it does provide significant long-lasting habitat.

    • Ummmmm, we are talking about Forest Service salvage projects, which some people want to paint as “salvage clearcuts”. Snag thinning is a very valid fuels reduction activity, which doesn’t clearcut lands. Preservationists simply see incinerated lands as some kind of “habitat”, regardless of how “natural” it really is. Take the Rim and King Fires, for example. Both were man-caused wildfires and the serial litigators claim it is “owl habitat”, or “blackbacked woodpecker habitat”. They even seem to be fine with converting owl and goshawk nesting habitats into future brushfields, devoid of conifers that such birds need to survive and reproduce. Yes, the “Whatever Happens” mindset continues to be strong, even when hundreds of square miles are converted into barren wastelands. We have seen that happen in Yosemite, where no salvage logging has occurred, and re-burns cause catastrophic “disturbance”, whether man-caused, or “natural”. In fact, one might say that man-caused wildfires are, indeed, “natural”, if you want to go that route.

  4. Here is an example of a re-burn that happened in a salvaged post-fire landscape.:

    https://www.google.com/maps/@38.4771147,-120.3477064,379m/data=!3m1!1e3?hl=en

    And here is an example of a re-burned post-fire landscape without salvage logging:

    https://www.google.com/maps/@37.7082949,-119.7552253,402m/data=!3m1!1e3?hl=en

    Of course, the second example doesn’t reflect last year’s re-burn, making it the second re-burn since 1989. Now, which landscape will have endangered and threatened species on it first? (I rest my case, here in the Sierra Nevada.)

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