Selway-Bitterroot Wilderness Research Articles

Mesic mixed-conifer forests are resilient to both historical high-severity fire and contemporary reburns in the US Northern Rocky Mountains

High-severity fires and short-interval reburns strongly influence forest structure and composition and may overwhelm forest ecosystem resilience and catalyze persistent shifts to non-forest conditions. Recent increases in annual area burned and severity in the western United States (US) highlight the need to better understand the long-term effects of high-severity fire, including interactions with subsequent fires. In the early 20th century, the northern US Rocky Mountains experienced several fire seasons with widespread, high-severity fires, under fire weather comparable with extreme conditions today. The Selway-Bitterroot Wilderness in north-central Idaho has remained an active fire regime with limited suppression and management, making it an ideal location to investigate long-term effects of initial high-severity fires, as well as ecosystem resilience to contemporary reburning. Using field sampling informed by fire history data from 1870 to 2020, we investigated the influence of fire frequency (once, twice, and thrice burned from 1910 to 2017) on forest structure, conifer regeneration, and fuel loading in mesic mixed-conifer forests that burned at high severity in either 1910 or 1934. Tree regeneration was abundant across all three burn histories, and 99% of sample sites were <200 m from the nearest conifer seed source when sampled in 2021. Abundance of snags and coarse woody material was less affected by fire frequency and more impacted by time since last fire. High shrub biomass occurred only on steep southwest aspects with low overstory basal area and was not related to burn history. Live tree composition and density differed across forests with contrasting recent fire histories, but even thrice-burned sites supported abundant conifer tree regeneration, indicating that northern Rocky Mountain mesic mixed-conifer forests that experienced fire during the twentieth century currently remain resilient to wildfire. Wildfire as an ecological process in the Selway-Bitterroot Wilderness likely contributed to ecosystem resilience.

Multidecadal trends in area burned with high severity in the Selway-Bitterroot Wilderness Area 1880–2012

Multidecadal trends in areas burned with high severity shape ecological effects of fires, but most assessments are limited to ~30 years of satellite data. We analysed the proportion of area burned with high severity, the annual area burned with high severity, the probability areas burned with high severity and also the area reburned (all severities and high burn severity only) over 133 years across 346265ha within the Selway-Bitterroot Wilderness (SBW) Area in Idaho, United States. We used burn severity class inferred from digitised aerial photography (1880–2000) and satellite imagery (1973–2012). Over this long record, the proportion burned with high severity did not increase, despite extensive area burned in recent decades. Much greater area burned with high severity during the Early (1880–1934) and Late (1975–2012) periods than during the Middle period (1935–1974), paralleling trends in area burned. Little area reburned with high severity, and fires in the Early period limited the extent of fires burning decades later in the Late period. Our results suggest that long-term data across large areas provides useful context on recent trends, and that projections for the extent and severity of future fires must consider prior fires and fire management.

Grizzly West: A Failed Attempt to Reintroduce Grizzly Bears in the Mountain West . By Michael J. Dax.

Grizzly West: A Failed Attempt to Reintroduce Grizzly Bears in the Mountain West . By Michael J. Dax. (Lincoln: University of Nebraska Press, 2015. xii + 289 pp. Illustrations, maps, notes, bibliography, index. $37.50, CAN$46.95, £23.99.) Michael J. Dax has written a book about a species reintroduction that never was. Unlike the popular and much written about gray wolf reintroduction in Yellowstone National Park, the proposed grizzly bear reintroduction to the Selway-Bitterroot Wilderness of Idaho and Montana was stillborn. Dax uses a juxtaposition of the Old West versus the New West to explain the ongoing seven-decade absence of grizzlies from their former domain. Dax opens with the complete extirpation of grizzly bears in the Bitterroots by trophy hunters, ranchers, and farmers by 1946. Grizzly bears’ bad press as a menace to … Mark_madison{at}fws.gov

Introduction to the Article by Elers Koch: The Passing of the Lolo Trail

In 1935, Elers Koch argued in a Journal of Forestry article that a minimum fire protection model should be implemented in the backcountry areas of national forests in Idaho, USA. As a USDA Forest Service Supervisor and Assistant Regional Forester, Koch had led many major fire-fighting campaigns in the region, beginning with the great 1910 fires of Idaho and Montana. He argued in his classic article for wilderness values, and against throwing millions of dollars into unsuccessful attempts to suppress back-country fires. His article was accompanied by a response from Earl Love-ridge, a proponent of full fire suppression, who was a leader of fire control from the Forest Service Washington Office. Loveridge soon after successfully proposed what was to become known as the 10 AM Policy—a universal fire suppression policy that lasted into the 1970s. While Koch’s classic article was not immediately successful in bringing about the backcountry “let burn” fire policy he sought, it did contribute to the designation of the Selway-Bitterroot Primitive Area in 1936, which became a congressionally designated wilderness area in 1964 with the passing of the Wilderness Act. With that, the stage was set for a new era in Forest Service fire management, and in 1972 the White Cap Creek drainage in the Selway-Bitterroot Wilderness became the first exception to the 10 AM Policy, realizing Koch’s vision.

Characterizing Fire-on-Fire Interactions in Three Large Wilderness Areas

The interaction of fires, where one fire burns into another recently burned area, is receiving increased attention from scientists and land managers wishing to describe the role of fire scars in affecting landscape pattern and future fire spread. Here, we quantify fire-on-fire interactions in terms of frequency, size, and time-since-previous fire (TSPF) in three large wilderness areas in Montana and Idaho, USA, from 1984 to present, using spatially consistent large fire perimeter data from the Monitoring Trends in Burn Severity (MTBS) dataset. The analysis is supplemented with less consistent fire perimeter data from a regional fire atlas in order to examine the potential role played by smaller fires in fire-on-fire interactions. We compare current rates of burning to existing estimates using the natural fire rotation (NFR) to determine whether recent fire activity falls within established historical ranges. We also compare actual fires to randomly located fires to establish whether the frequency and size of re-burns differ by chance. Finally, we systematically classify shared fire edges as fire-stopping or breached to quantify the effect of previous fires on subsequent fire spread. In total, more than half of the Frank Church, one-quarter of the Bob Marshall, and fifteen percent of the Selway-Bitterroot wilderness areas have burned since 1984. Area burned within each of the study areas yielded NFRs that are consistent with results derived from fire atlas and tree-ring research studies. The data show that re-burning occurs less frequently than chance in the Frank Church Wilderness Area, perhaps less frequently in the Bob Marshall Wilderness Area, and the same as chance in the Selway-Bitterroot Wilderness Area. In each of the study areas, the total amount of edge at which a fire met another fire was less than three percent of the total available perimeter. However, ∼80 % of the total edge encountered was breached, resulting in fire spreading onto previously burned landscapes and re-burning at least 40 ha. Year-to-year variability in re-burn occurrence was high, and the size of re-burns was typically small, implying a general resistance to re-burning, but the preponderance of small patches resulting from fire interactions has perhaps significant ecological implications. There was a systematic decrease in the frequency of small to medium sized re-burns (40 ha to 405 ha) as time between fires increased in all three wilderness areas. The frequency of large re-burns increased with time in the Frank Church wilderness area, but this trend was not apparent in the other two wilderness areas. Overall, fire-on-fire interactions show a high degree of complexity, making direct comparisons between the three wilderness areas difficult, but the evidence suggests that large wildfires generally inhibit the spread of subsequent fires, while small fires appear to have little impact on the spread of other fires. The limiting effect of large fires on small fires is potentially significant based on the number of cases observed (n = 101).

Listening to the Land: The Selway-Bitterroot Wilderness as Oral History

Although there have been oral histories made of wilderness activists such as Wallace Stegner, oral history and pristine wilderness are seldom paired. Wilderness, as defined by the 1964 Congressional Act is, “in contrast with those areas where man and his own works dominate the landscape, [wilderness] is hereby recognized as an area where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain.”1 Given this definition, human history is often neglected in wilderness literature. This is especially true of places like the Selway-Bitterroot Wilderness, the third largest of such areas in the continental U.S. as well as one of the most remote. Yet, however, “untrammeled” this landscape appears to be, in fact it has a complex human history. Representing this history is best done through the medium of oral narrative since orality holds the ability to preserve a sense of time and place, and sound is the fullest way to transform a real space into an imaginary one. Oral narratives of the Selway-Bitterroot, and by extension many American wildernesses, are vital to understanding the interconnectedness between cultural and natural environments. These narratives get closest to the experiencing body in real time, which is what understanding wilderness requires.

Wildfire and Charcoal Enhance Nitrification and Ammonium‐Oxidizing Bacterial Abundance in Dry Montane Forest Soils

All forest fire events generate some quantity of charcoal, which may persist in soils for hundreds to thousands of years. However, few studies have effectively evaluated the potential for charcoal to influence specific microbial communities or processes. To our knowledge, no studies have specifically addressed the effect of charcoal on ammonia-oxidizing bacteria (AOB) in forest soils. Controlled experiments have shown that charcoal amendment of fire-excluded temperate and boreal coniferous forest soil increases net nitrification, suggesting that charcoal plays a major role in maintaining nitrification for extended periods postfire. In this study, we examined the influence of fire history on gross nitrification, nitrification potential, and the nature and abundance of AOB. Soil cores were collected from sites in the Selway-Bitterroot wilderness area in northern Idaho that had been exposed twice (in 1910, 1934) or three times (1910, 1934, and 1992) in the last 94 yr, allowing us to contrast soils recently exposed to fire to those that experienced no recent fire (control). Charcoal content was determined in the O horizon by hand-separation and in the mineral soil by a chemical digestion procedure. Gross and net nitrification, and potential rates of nitrification were measured in mineral soil. Analysis of the AOB community was conducted using primer sets specific for the ammonia mono-oxygenase gene (amoA) or the 16S rRNA gene of AOB. Denaturing gradient gel electrophoresis was used to analyze the AOB community structure, while AOB abundance was determined by quantitative polymerase chain reaction. Recent (12-yr-old) wildfire resulted in greater charcoal contents and nitrification rates compared with sites without fire for 75 yr, and the more recent fire appeared to have directly influenced AOB abundance and community structure. We predicted and observed greater abundance of AOB in soils recently exposed to fire compared with control soils. Interestingly, sequence data revealed that Clusters 3 and 4, and not Cluster 2, of genus Nitrosospira dominated these forest soils, with a shift toward Cluster 3 in recently burned sites.

Complexity of Successional Pathways in Subalpine Forests of the Selway-Bitterroot Wilderness Area

We examined forest structure and composition in four watersheds in the Selway-Bitterroot Wilderness Area, Idaho and Montana, to better understand the complexity of successional processes following stand-replacing fires in subalpine forest ecosystems. Dendrochronological analyses of more than 1,100 trees were used to identify the timing of establishment of major forest species at sites that had experienced different intervals since the last fire. This was coupled with analyses of forest structure and composition using nonmetric multidimensional scaling. A conceptual model of stand development is presented to highlight our findings. Lodgepole pine (Pinus contorta var. latifolia Dougl.) dominated most overstories for the first 100–200 years but persisted as a canopy dominant for more than 250 years in some stands. As forests increased in age, Engelmann spruce (Picea engelmanii Parry) and subalpine fir (Abies lasiocarpa [Hook.] Nutt.) became more prominent in the overstory. Whitebark pine was present in some young stands and older stands but was most often represented as dead standing trees killed during twentieth-century mountain pine beetle outbreaks. Understory composition was a function of time-since-fire but showed considerable variation that is likely tied to seed arrival, environmental conditions, and establishment. Our results suggest that short fire intervals may limit the development of lodgepole pines capable of producing serotinous cones, leading to young forests dominated by spruce or fir. However, intervals longer than the lifespan of lodgepole pine (as long as 350 years) could also lead to early dominance by spruce or fir following fire. These results refine our understanding of the temporal development of subalpine communities following stand-replacing fires and have implications for the implementation of long-range management goals in these habitats.

A Comparison of Fire Regimes and Stand Dynamics in Whitebark Pine (Pinus albicaulis) Communities in the Greater Yellowstone Ecosystem

Whitebark pine (Pinus albicaulis) is a keystone species of upper subalpine ecosystems (Tomback et al. 2001), and is especially important in the high-elevation ecosystems of the northern Rocky Mountains (Arno and Hoff 1989). Its seeds are an essential food source for the endangered grizzly bear (Ursus arctos horribilis), particularly in the autumn, prior to winter denning (Mattson and Jonkel 1990, Mattson and Reinhart 1990, Mattson et al. 1992). In the Greater Yellowstone Ecosystem (GYE), biologists have concluded that the fate of grizzlies is intrinsically linked to the health of the whitebark pine communities found in and around Yellowstone National Park (YNP) (Mattson and Merrill 2002). Over the past century, however, whitebark pine has severely declined throughout much of its range as a result of an introduced fungus, white pine blister rust (Cronartium ribicola) (Hoff and Hagle 1990, Smith and Hoffman 2000, McDonald and Hoff 2001), native pine beetle (Dendroctonus ponderosae) infestations (Bartos and Gibson 1990, Kendall and Keane 2001), and, perhaps in some locations, successional replacement related to fire exclusion and fire suppression (Amo 2001). The most common historical whitebark pine ftre regimes are "stand-replacement", and "mixed­ severity" regimes (Morgan et al. 1994, Arno 2000, Arno and Allison-Bunnell2002). In the GYE, mixed-severity ftre regimes have been documented in whitebark pine forests in the Shoshone National forest NW of Cody, WY (Morgan and Bunting 1990), and in NE Yellowstone National Park (Barrett 1994). In Western Montana and Idaho, mixed fire regimes have been documented in whitebark pine communities in the Bob Marshall Wilderness (Keane et al. 1994), Selway-Bitterroot Wilderness (Brown et al. 1994), and the West Bighole Range (Murray et al.1998). Mattson and Reinhart (1990) found a stand­replacing fire regime on the Mount Washburn Massif, within Yellowstone National Park.

Using simulation to map fire regimes: an evaluation of approaches, strategies, and limitations

Spatial depictions of fire regimes are indispensable to fire management because they portray important characteristics of wildland fire, such as severity, intensity, and pattern, across a landscape that serves as important reference for future treatment activities. However, spatially explicit fire regime maps are difficult and costly to create requiring extensive expertise in fire history sampling, multivariate statistics, remotely sensed image classification, fire behaviour and effects, fuel dynamics, landscape ecology, simulation modelling, and geographical information systems (GIS). This paper first compares three common strategies for predicting fire regimes (classification, empirical, and simulation) using a 51�000�ha landscape in the Selway-Bitterroot Wilderness Area of Montana, USA. Simulation modelling is identified as the best overall strategy with respect to developing temporally deep spatial fire patterns, but it has limitations. To illustrate these problems, we performed three simulation experiments using the LANDSUM spatial model to determine the relative importance of (1) simulation time span; (2) fire frequency parameters; and (3) fire size parameters on the simulation of landscape fire return interval. The model used to simulate fire regimes is also very important, so we compared two spatially explicit landscape fire succession models (LANDSUM and FIRESCAPE) to demonstrate differences between model predictions and limitations of each on a neutral landscape. FIRESCAPE was developed for simulating fire regimes in eucalypt forests of south-eastern Australia. Finally, challenges for future simulation and fire regime research are presented including field data, scale, fire regime variability, map obsolescence, and classification resolution.

Evaluating a century of fire patterns in two Rocky Mountain wilderness areas using digital fire atlases

Changes in fire size, shape, and frequency under different fire-management strategies were evaluated using time series of fire perimeter data (fire atlases) and mapped potential vegetation types (PVTs) in the Gila – Aldo Leopold Wilderness Complex (GALWC) in New Mexico and the Selway–Bitterroot Wilderness Complex (SBWC) in Idaho and Montana. Relative to pre-Euro-American estimates, fire rotations in the GALWC were short during the recent wildfire-use period (1975–1993) and long during the pre-modern suppression period (1909–1946). In contrast, fire rotations in the SBWC were short during the pre-modern suppression period (1880–1934) and long during the modern suppression period (1935–1975). In general, fire-rotation periods were shorter in mid-elevation, shade-intolerant PVTs. Fire intervals in the GALWC and SBWC are currently longer than fire intervals prior to Euro-American settlement. Proactive fire and fuels management are needed to restore fire regimes in each wilderness complex to within natural ranges of variability and to reduce the risk of catastrophic wildfire in upper elevations of the GALWC and nearly the entire SBWC. Analyses of fire atlases provide baseline information for evaluating landscape patterns across broad landscapes.

Comparisons of Particulate-Emissions and Smoke Impacts From Presettlement, Full Suppression, and Prescribed Natural Fire Period in the Selway-Bitterroot Wilderness

Total particulate matter (PM) emissions were estimated for recent fires (1979-1990) and the presettlement period (prior to 1935) in the Selway-Bitterroot Wilderness (SBW) in Idaho and Montana. Recent period emissions were calculated by 10-day periods for surface fire and crown fire based on estimates of percentage fuel consumption and emission factors applied to fuel models constructed for each of eight fire regime types. Presettlement emissions were derived from estimates of historical fire occurrence. The occurrence and duration of smoke episodes in a large adjoining valley were documented for a 30-year period (1960-1990). During the presettlement period, smoke emissions were 1.3 times greater than during the recent period. Dispersion modeling indicated that during presettlement, visibility averaged 25% less than during the recent period. Valley smoke episodes ranged from 2 to 10 days in length and were 1.3 times more likely to occur during the presettlement period. Regression analysis indicated that a valley smoke event was likely above a 10-day PM threshold of 1,500 Mg. Characteristics of smoke episodes were described for none, minor, moderate, and extreme smoke categories. Occurrence of smoke did not differ between periods of full fire suppression and prescribed natural fire management.

Comparing the Prescribed Natural Fire Program With Presettlement Fires in the Selway-Bitterroot Wilderness

The severity and extent of recent fires (1979-1990) were compared with that of presettlement fires (pre-1935) by eight major forest types in the Selway-Bitterroot Wilderness (SBW) in Idaho and Montana. Presettlement fire intervals were determined for estimating area burned. Presettlement annual area burned for the entire SBW was 4,290 ha by stand replacement fire and 4,310 ha by nonlethal understory fire. All recent period fires&gt;4 ha were mapped using a GIS system. Area burned was determined by the fire severity classes: crowning, lethal surface, nonlethal surface, and no burning. Annual area burned averaged 2,780 ha by stand replacement and 2,270 by understory fire. Area burned during presettlement was 1.7 times that during the recent period. During the presettlement period, area burned by stand replacement and nonlethal understory fire was 1.5 and 1.9 times greater respectively than during the recent period.

Effects of Sample Preparation, Growth Stage, and Observer on Microhistological Analysis of Herbivore Diets

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Fire-dependent forests in the Northern Rocky Mountains

One objective of wilderness and parkland fire-ecology research is to describe the relationships between fire and unmanaged ecosystems, so that strategies can be determined that will provide a more nearly natural incidence of fire. More than 50 yr of efforts directed toward exclusion of wildland fires in the Northern Rocky Mountains (western Montana and northern Idaho) have resulted in a definite and observable impact on the forest ecosystems in this region. Fire-ecology investigations in Glacier National Park and the Selway-Bitterroot Wilderness have helped to reveal the nature of this impact and to provide a better understanding of the natural role of fire within these coniferous ecosystems. Such areas provide a unique opportunity to study and test approaches designed to perpetuate unmodified ecosystems. However, we still don't understand all of the long-term consequences of fire control in those forest communities that have evolved fire-dependent characteristics.

A study of reproduction, disease and physiological blood and serum values in Idaho elk.

A study was conducted on elk (Cervus canadensis nelsoni) in the Selway-Bitterroot Wilderness and adjoining primitive area of the Clearwater drainage of Idaho over a 3 year period, 1969-1972. Midwinter examination of cows in this herd indicated the pregnancy rate was high, but game counts showed only 15 to 20 calves per 100 cows indicating that the losses occurred around or after calving. A serologic survey did not indicate the presence of antibodies to the agents of brucellosis, leptospirosis, vibriosis, bluetongue, infectious bovine rhinotracheitis or bovine virus diarrhea. Positive complement fixation reactions for anaplasmosis were present in nearly 50% of the animals tested; however, many of the serums were anticomplementary. Blood chemistry determinations were made on all elk and compared with the values obtained from captive elk. Similar values were noted in the captive and wild elk in calcium phosphorous ratio, glucose and total protein. Dissimilarity occurred with cholesterol, blood urea nitrogen,...

Determining Elk Movements through Periodic Aerial Counts

This paper presents a report on the use of periodic aerial surveys to ascertain elk movements and migration patterns. As an attempt to add to the store of knowledge relating to the elk of Idaho, the Idaho Fish and Game Department and the Idaho Cooperative Wildlife Research Unit initiated a study in the Selway-Bitterroot Wilderness Area of north central Idaho (Robel, 1958). Aerial censusing of big game populations is a common practice of most game departments. Ruhl (1932) felt that aerial censusing was too expensive to be practical in wildlife management. Later, as flight time became less expensive and the value of wildlife became more apparent, aerial censusing of most big game animals evolved into an acceptable technique. The applicability of aerial censusing is dependent upon many factors, including terrain, cover, etc. Matteson (1950) reported that by 1950, most states with elk populations were using airplanes to census their herds. In many instances, the knowledge of an elk population size alone is not sufficient for an intelligent management program. An insight into migration routes and the time of these migrations is at times extremely valuable to the big game manager. In an attempt to develop methods to obtain this information, both air and ground surveys of elk were conducted in the Selway district of Idaho in the winter of 1957-1958.