PNW Pacific Northwest Research Station INSIDE in the Path of Destruction ...... 2 Soil and Water in the Path of Destruction . . .3 Recoup the Value or Preserve the ? . . .3 Assessing the State of Knowledge ...... 4 Trial By Fire ...... 4 FINDINGS issue forty-seven / october 2002

“Science affects the way we think together.” Lewis Thomas

POSTFIRE : IS IT BENEFICIAL TO A FOREST?

here’s the viewpoint that says if you log after a fire it’s like IN SUMMARY T mugging a burn victim. And there’s the viewpoint that says if you don’t Public debate on postfire logging has log after a fire you’re guaranteeing more intensified in recent years, particularly and worse damage to come because of fuel buildup. The viewpoints in between are since passage of the “salvage rider” in rarely heard above the fracas. 1995, directing accelerated harvest of dead “The controversy over how to conduct trees in the western United States. postfire logging, or whether to conduct it at all, gets more intense in any area expe- Supporters of postfire logging argue that it riencing fires,” says Jim McIver. “There has historically been a rush to get usable is part of a suite of restoration techniques, timber off a burn site before the beetles and that removal of timber means reduc- move in, and agency planning processes tion of fuels for future fires (the “reburn” are not set up to deal with this rush.” effect). Opponents argue that it causes Neither, apparently, are the available science data capable of dealing with the damage to burned sites, particularly to rush. “As environmental debate heated up soils, that it increases sediment transport, on the salvage issue in the mid and late 1990s, it became obvious that there was and that it removes large dead trees that little documented science background for have important ecological functions. the views of either side,” notes McIver, a research ecologist with the and Considerable debate about the merits of Range Sciences Laboratory, PNW postfire logging has been carried on with- Research Station, in La Grande, Oregon. Photo credit: K.Wattenmaker, National Interagency Fire Center Photo credit: K.Wattenmaker, out benefit of much scientific information. Severe kills many trees leading An interesting statistic helps explain why ➢ to a heated public debate: log it the so-called salvage logging debate blew A recent review drew together the avail- or leave it? up so fast. able scientific literature on postfire Because of the dramatic reduction in logging. At the same time, an experimental “The debate on the policy of post- green- harvest after emergence of the study in eastern Oregon was designed to fire logging has been carried on spotted owl crisis in the early 1990s, the percentage of dead-tree harvest by the without the benefit of much test the “reburn” hypothesis and to exam- Forest Service in National of ine soil and sediment transport in a major direct scientific information.” Oregon and Washington rose from 14 Jim McIver percent of overall harvest in the 1980s to postfire logging operation. 21 percent in the mid-1990s. In the Wallowa-Whitman National Forest, taken KEY FINDINGS alone, the rise was more dramatic for those decades—from 24 to 70 percent. • The immediate environmental effects of postfire logging depend on the severity of the burn, slope, soil texture and composition, the presence or building of The proportional change brought the roads, type of logging system, and postfire weather conditions. salvage programs rapidly into the spot- light, and the battle of words was begun. • Postfire logging can cause significant changes in the abundance and nest When the “salvage rider” directed federal density of cavity-nesting birds, particularly those attracted to recently burned land management agencies in 1994 to forests. accelerate harvest of dead trees in the western United States, the noise reached a • The probability that insect pest populations will build up and infest adjacent- crescendo. As always, polarization was green-tree stands may be reduced through removal of vulnerable trees after fire. right behind. • Fuel mass increased on the logged sites as a result of slash left over from A closer look at the conditions fire harvest, and on the control site as the result of fire-killed trees falling over. produces across dry landscapes helps clar- ify the arguments.

TREES IN THE PATH OF DESTRUCTION “ hen wildfire sweeps across a of insects tends to attract insectivorous landscape, obviously the most birds, such as the black-backed - Purpose of W conspicuous result is dead or pecker in eastern Oregon’s Blue PNW Science Findings dying vegetation, particularly trees,” says Mountains. McIver. “Although extremely intense To provide scientific information “As a consequence of changes in food forest fires potentially can consume all to people who make and influence composition and breeding habitat, burned decisions about managing land. aboveground , normally a much forests typically support significantly lower percentage is consumed, even in PNW Science Findings is published different bird communities, with many so-called stand-replacement fires.” monthly by: species dependent on stand-replacement Percentages are affected by variables such Pacific Northwest Research Station fires to maintain their populations across as fire intensity, fire duration, weather, USDA Forest Service the landscape,” he says. “Usually there’s topography, fuel moisture, stand composi- P.O. Box 3890 an increase in cavity-nesting, insectivo- tion, and structure. Species composition, Portland, Oregon 97208 rous birds such as woodpeckers and along with stem size and age, also play (503) 808-2137 certain species of flycatchers.” roles in levels of plant death. Sherri Richardson Dodge, Editor Plant succession after a fire also affects [email protected] Trees killed by wildfire and left standing wildlife response. Species composition of take on roles that change the ecological Send new subscriptions and change bird communities, for example, is altered services they previously provided as of address information to first by the fire itself, then by development components of a green-tree system. They [email protected] of a shrub stage, and then by the advanc- still offer some shade, which in a burned ing young tree community. Carlyn Mitas, Design & layout environment can slow the heating of surface [email protected] waters and the soil surface. They may also Similarly, mammal species composition is provide more rapid recruitment of large changed by wildfire; everything from deer wood into streams. Decomposing fallen and elk to small forest-floor mammals trees provide nutrients, shelter, and early have compositional responses to fire. structure for a rejuvenating forest floor. Wildfire, like any other large-scale distur- United States Forest Service bance, including management, will favor Department of With the arrival of beetles, the dynamic some species and reduce the occurrence of Agriculture changes more dramatically. Dead trees others. McIver points out that a full histor- attract a wide variety of bark and wood- ical mix of species across the landscape boring beetle species, which can build up depends on a shifting mosaic of landscape large populations that serve as a source for conditions, to which fire is a crucial infestation of adjacent green-tree stands, contributor. McIver explains. The increased abundance

Science Findings is online at: http://www.fs.fed.us/pnw

2 SOIL AND WATER IN THE PATH OF DESTRUCTION oil changes alter hydrology, erosion rates, stream characteristics, and LAND MANAGEMENT IMPLICATIONS S vegetation regrowth. Under severe burning, soils can become water repellant. • There is so much variation in burned forests, and so much variation in logging This occurs in depths proportional to the equipment used, that small-scale experimental studies are unlikely soon to intensity of burn, so severe burns can provide general principles for mitigating ecological damage in the postfire envi- reduce functional soil depth from several ronment. feet to several inches. McIver adds that tree death contributes to lower rates of evapo- • Managers could benefit by comparing different practices and prescriptions transpiration, so that postfire soils tend to applied to similar stands in an operational context, even if such comparisons remain more saturated and less able to were unreplicated or uncontrolled. In other words, adaptive management may accept water from big precipitation events. be the best tool at hand. “The result is increased overland flow capa- • The Summit fire results suggest that by using logging over snow in areas with ble of carrying more sediment, and therefore heavy soils and low slope, postfire logging can be conducted with relatively able to cause more erosion. Combined with little transfer of sediment to perennial streams. the removal of vegetation by fire, erosion potential can be very high compared with Streams within burned areas may suffer areas are presumably adapted to the unburned watersheds,” he says. many related fire effects: loss of woody mosaic of landscape patterns created by In addition, fire usually results in the loss debris sources, increased sediment and natural regimes. or alteration of nutrients, and sometimes nutrient transport, increased water temper- With these well-known effects of wildfire, the exposure of mineral soils. These ature, changes in magnitude and timing of particularly of more intense burns, what of changes can significantly affect site peak flows, and decreased habitat diver- the debate about postfire logging? productivity. sity. Nonetheless, fish species in these

RECOUP THE VALUE OR PRESERVE THE FOREST? tandard practice on federal lands contour, and cross-ditching of skid trails – is compacted by snow. Similarly, the slash has been to harvest trees soon after all to reduce postfire erosion. Tree bole left by logging initially increases fuels S fire. Objectives can be ecological— removal is designed to slow drip erosion at available to burn if the fuels are not treated rehabilitation and restoration—or the base of fire-killed trees. Timber immediately; but the fuel level rapidly economic—seeking to recoup as much removal is believed to slow buildup of drops as the slash decays and compacts.” economic value as possible before trees insect populations, and remove fuel from Opponents of postfire logging argue that begin to decay, and particularly before the path of subsequent fires. The latter, the logging causes damage to burned sites as a beetles arrive to hasten the process. In “reburn hypothesis,” contends that the result of the harvest operations them- Ponderosa pine stands, the beetles gener- removal of dead trees after a fire can selves, or removes structure that has ally arrive at major fire sites within reduce fuels and thus the intensity of fires important ecological functions, particu- months or years, and their feeding can that may occur in the future. larly the habitat provided by both standing lower economic value significantly within “You have to look closely at the type of and down wood. “In particular, it has been a year or two following infestation. material brought down by a fire, though,” suggested that postfire logging operations “Land managers generally have a strong says Roger Ottmar, a research exacerbate local or watershed effects tendency to do some form of active with the Seattle laboratory of the PNW induced by fire, such as erosion, nutrient management after a fire. In many cases, Research Station, who provided methodol- loss, and the introduction of exotic plant they view logging as one component in an ogy and data reduction for a recent postfire species, and that as a consequence, stan- array of rehabilitation and restoration tech- logging experiment undertaken by McIver. dards and guides should be at least as strict niques, many designed to mitigate adverse on burned sites as on ‘green-tree’ sites,” “If it is left unlogged, it may indeed environmental effects perceived to be due McIver explains. increase fire hazard as the fire-killed trees to the fire itself,” McIver says. begin to fall and add fuels to the ground. For example, an oft-cited report by Robert Such measures include scattering of However, that hazard drops dramatically Beschta and colleagues in 1995 recom- logging slash, placement of logs on the over the years as the material decays and mended a passive (i.e., “hands-off”)

WRITER’S PROFILE Sally Duncan is a science communications consultant and writer specializing in forest resource issues. She lives in Corvallis, Oregon, and is a doctoral candidate in environmental sciences at Oregon State University.

3 approach to both wildfire and postfire logging activity, and the idea of reducing the associated practices of rehabilitation, management in light of inferred, predomi- dangerous fuel accumulations through such as planting and seeding, that typically nantly adverse effects of active manage- salvage logging. McIver and Lynn Starr occur after harvest. Geographic scope of ment practices (including salvage concluded a literature review that summa- the review was the dry, forested inter- logging). rized information through February 2000 mountain West, with some work from on the environmental effects of salvage other parts of the country and the world, With little direct scientific data to support harvest in fire-killed forests. all involving forest types with relatively either position, closer examination was short fire-return intervals. warranted for both the custodial approach The review focused on the environmental aimed at protecting postfire areas from any effects of timber harvest itself, and not on ASSESSING THE STATE OF KNOWLEDGE nly 14 studies isolated the actual “When you run machines over a burned Removal of dead trees, of course, has its effect of logging of burned site, you’re more likely to get increased impacts on wildlife. Four studies in the O timber compared to an unlogged compaction and displacement,” says mid-1990s demonstrated that black-backed control. Another seven documented McIver. He adds that although logging can woodpeckers are less attracted to burn “management experiments” in which the increase sediment movement over and sites that have large dead trees removed, effects of various management treatments above what fire has already done, certain and it’s almost always the large trees that were compared without an unlogged logging systems mitigate such effects. get removed first if economics is the control. Without the control, McIver Logging over snow, using aerial logging driver, McIver points out. points out, it is difficult to determine the systems, using grabbing systems rather “The boom and bust of species composi- relative contributions made by fire versus than skidding for log retrieval, and mini- tion occurs on the backs of fires,” he logging. mizing site entry in general, all help to explains, “and removing those big trees keep soil problems down. Nonetheless, many of the available findings removes habitat for wildlife.” Creating and concur on issues pertaining to postfire Most soil movement after a fire appears to destroying habitat are the potential twin logging. Just like in green forests, road- take place in the first few years. If a site results of fire, just as they need to be building is likely to cause the greatest can hold steady for about 5 years (until it considered as potential twin outcomes of increase in sediment transport off-site. And develops some shrubs and some return of postfire logging. burned forests themselves, most researchers the forest floor structure) soils will also agree, are at least as sensitive as green have lost their water repellancy, and forests, and the same care and attention damage will be reduced. needs to be paid to their management.

TRIAL BY FIRE he immediate environmental logging and just take a look at what some skidder to tow whole trees back to land- effects of postfire logging depend of the differences are. Create new knowl- ings. The skidder traveled on a limited T on the severity of the burn, slope, edge. Sprinkle a variety of prescriptions number of main trails to which logs were soil texture and composition, the presence across the landscape, kind of like Nature yarded and stacked from where they were or building of roads, type of log retrieval does. See what happens,” McIver says. felled. No new roads were built. systems, and postfire weather conditions,” At one site in eastern Oregon, McIver has The focus of the study was on soil impacts “Ottmar notes. “The complexity of these been able to test some postfire logging and reburn potential. The experimental elements makes study of any one site diffi- hypotheses, including the one that states study found that the use of logging cult, and makes it almost impossible to adaptive management would yield the machinery disturbed between 8 and 20 extrapolate results to other sites, especially most results. The 1996 Summit fire burned percent of soil area in the study units, with without controls.” The normal delay of across 40,000 acres in the Umatilla and displacement and compaction the principal research, he adds, means that although we Malheur National Forests, with varying types of disturbance. Sediment transport now have far greater priority for the post- intensity. Four replicates of three treat- out of the area was minimal, probably fire logging question, we still have only ments were established the following year because the slopes were low, and no new very preliminary answers. at low elevations, in areas historically roads were constructed. A perfect setting for adaptive manage- dominated by ponderosa pine. One treat- Logging removed between 43 and 46 ment. “With the numerous variations that ment was no postfire logging, one logged percent of timber basal area, a significant occur within and between sites, cloud- one-third of the remaining viable timber, amount when viewed in terms of habitat, bursts that affect one small area and not and one logged all of the remaining viable for this is likely to change the abundance another, and other unique responses, adap- timber. and nest density of certain fire-dependent tive management offers the chance to The logging was done over snow, with a birds. leave some stands untouched by postfire feller-buncher to cut the trees down, and a

4 “But the jury is still out on the reburn decay, plenty of fuel for subsequent fires Post-logging Fuel Loads question,” Ottmar says. “All size classes of for up to 50 years. woody fuels actually increased on the The Summit postfire logging study logged as well as control units in the 16 suggests that logging can be done with experiment. But logging added more 14 acceptable effects on soils and minimal 12 small-diameter woody fuel in the short sediment transport off-site, provided the 10 term due to handling of the felled logs. 8 right equipment and approach are used, This resulted in slightly higher post- 6 McIver says. “Studies are needed that 4 logging fuel loads in the harvested units.” measure sediment transport at drainage 2 Yet logging also reduced the amount of 0 scales and adaptive management experi- per Tons Acre Average standing fuel, in the form of dead trees, he Control Partial Salvage Full Salvage ments to see how site differences play notes. As these dead trees fall down, they Treatment out,” he adds. Twigs will contribute to future fuel loads. If their Logs decay rate is fast and the next fire doesn’t The Summit study is only a little step on happen for a long while, the initial fuel one site, and the researchers are very wary Average post-logging fuel loads in con- ➢ differences between control and salvage of applying its results to other places. trol, partial, and full salvage units at the Summit fire. won’t matter much. But if decay rate is Needed, they say, are more studies of large slow, or if the next fire happens soon, then fire events, instrumented green and burned a “reburn” effect could occur, Ottmar landscapes, and well-designed research Post-logging Basal Area explains. augmented by adaptive management to see how site differences play out. Fuel load- Model projections reveal that logged units 70 ings, fuel treatments, and reburn potential might have less fuel in the long run and ft2/ac) 60 remain complex and challenging issues. may burn less intensely. But, and it is a big 50 “but,” the rates of decay of down material The debate, as people slowly become 40 make a huge difference to these results. better informed, will no doubt continue. 30 20 Rapid decay, rapid loss of fuel. Slow 10 0 Control Partial Salvage Full Salvage

FOR FURTHER READING ( Area Basal Average Treatment Klock, G.O. 1975. Impact of postfire salvage logging systems on soils and vegetation. Journal of Soil and Water Conservation. 30 (2): 78-81. Average post-logging basal areas for ➢ control, partial, and full salvage units at McIver, J.D.; Starr, L. 2001. A literature review on the environmental effects of postfire the Summit fire. logging. Western Journal of Applied Forestry. 16 (4): 159-168. McIver, J.D. [and others]. [N.d.] Fuel reduction, soil impacts, and sediment transport after postfire logging in northeastern Oregon. To be submitted to and Management. STATION LAUNCHES NEW PUBLICATION Saab, V.J. Dudley, J. 1998. Responses of cavity-nesting birds to stand-replacement fire and salvage logging in ponderosa pine/Douglas-fir forests of southwestern Idaho. Res. Pap. Science Update, a 12-page RMRS-RP-11. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. color publication, offers scien- tific knowledge for pressing decisions about controversial natural resource and environ- mental issues. It can be found online at the PNW Research Station Website at www.fs.fed.us/pnw.

5 PRSRT STD US POSTAGE PAID PORTLAND OR FINDINGS PERMIT N0 G-40 U.S. Department of Agriculture Pacific Northwest Research Station 333 S.W. First Avenue P.O. Box 3890 Portland, OR 97208-3890

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SCIENTIST PROFILES JIM MCIVER is a research ecologist with the develop a natural fuels photo series, fuel consumption models Disturbance Team, Managing Disturbance for forested and nonforested fuel types; and a new fuel charac- Regimes Program of the Pacific Northwest terization system for the United States. Ottmar recently Research Station. His research interests completed research to assess fuel loading, fire behavior, and include evaluation of fire and fire-surrogate emissions from different management scenarios in the interior treatments for restoration of dry coniferous Columbia River basin. He also assessed wildland firefighter forests, the relations of arthropods to invasive exposure to smoke and the associated health risk. plants, and the ecology of social insects. Ottmar can be reached at: McIver can be reached at: Pacific Northwest Research Station/USDA Forest Service Pacific Northwest Research Station/USDA Forest Service Forestry Sciences Laboratory Forestry and Range Sciences Laboratory 4043 Roosevelt Way, NE 1401 Gekeler Lane Seattle, WA 98105 La Grande, OR 97850 Phone: (206) 732-7826 Phone: (541) 962-6528 E-mail: [email protected] E-mail: [email protected] COLLABORATORS ROGER OTTMAR is a research forester (All collaborators are USDA Forest Service employees) in the Fire and Environmental Research Robert McNeil, Malheur NF Applications Team, Managing Disturbance Steve Howes, Pacific Northwest Region Regimes Program of the Pacific Northwest Bob Brown, Rocky Mountain Research Station Research Station. He has conducted research Bill Elliot, Rocky Mountain Research Station in fuels, fire, and smoke for more than 22 Pete Robichaud, Rocky Mountain Research Station years. He is currently leading efforts to

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