Interior Northwest Research Articles

Fifteen-year tree growth on standard long-term soil productivity trials and various adjacent amelioration treatments at Interior Cedar-Hemlock sites in southeastern British Columbia and northern Idaho

Understanding the relationship between soil disturbance and tree growth is key to sustainable forest management. We report fifteen-year tree growth results of Douglas-fir (Pseudotsuga menziesii var. glauca [Beissn.] Franco) and western white pine (Pinus monticola Dougl. ex D.Don) growth following clearcut harvesting and installation of three replicates of the international Long-Term Soil Productivity (LTSP) trial protocols. Additional amelioration plots were also established on each replicate site to study rehabilitation of the most severe disturbance, treatment of Armillaria root disease, and enhancement of soil organic matter. Stark differences were found among the various treatments and species. Vegetation control resulted in significantly better growth for both tree species across the core LTSP treatments and amelioration treatments. On the core LTSP treatments, organic matter removal had a significant negative effect on Douglas-fir growth. Amelioration treatments resulted in similar survival and similar or better volume growth than the core LTSP treatments, with the exception of poor volume growth after compaction rehabilitation with no organic matter returned into the soil. Compaction significantly influenced Douglas-fir survival and was often higher on moderate compaction plots. On some sites there was decreased survival and growth associated with heavy compaction that will likely influence longer-term outcomes with a more variable and changing climate. Overall, results to date on the core LTSP treatments, amelioration treatments, and adjacent miniplots reported elsewhere suggest that forest floor removal causes negative growth and, combined with severe compaction, caused both negative growth and poor survival. In the Interior Northwest it is still prudent to minimize soil disturbance and leave organic matter onsite unless there is site specific evidence to the contrary. Additional work is required to reap the full, long-term benefit of the installations. Recommendations are provided highlighting the critical work that should be completed in the near future before biological evidence is lost to decay, including suggestions for further data analysis and extension, the need to continue LTSP core, amelioration and miniplot measurements to demonstrate and calibrate sustainable forest resource management. Our data suggest considering changes to current soil disturbance policy and forest operations based on the current results regarding forest floor displacement.

Species, Climatypes, Climate Change, and Forest Health: A Conversion of Science to Practice for Inland Northwest (USA) Forests

Research Highlights: This paper integrates disparate research results pertaining to climate change impacts to 12 co-occurring forest tree species and their climatypes such that management options for the ecosystem as a whole become discernible. Background and Objectives: The ecosystem under analysis is the Thuja-Tsuga forest ecosystem, occupying ca. 121,500 km2 in a largely mountainous setting in the interior northwest, USA. Our goal is to present land management options tied directly to climate-change in a straightforward framework for both the current and future generations. Materials and Methods: By merging synecological and genecological concepts in a climatic framework, we simplify complex interactions in a manner that relates directly to climate change impacts. Species and climatype distributions are redefined in terms of mean annual temperature and elevation of forested landscapes. Results: For each 2 °C increase in temperature, plant associations should shift upwards ca. 400 m, provided precipitation remains at or near contemporary levels, which, for this ecosystem, vary between 300 mm and 1450 mm. Management guidelines are developed for (a) selecting climatypes of the species suited to the climate at the leading edge of the migration front, (b) anticipating decline at the trailing edge, and (c) converting climatypes in areas where species should persist. Conclusions: Our results can provide robust strategies for adapting forest management to the effects of climate change, but their effectiveness is dependent on the implementation of global warming mitigation actions.

Gendered Places and Depositional Histories: Reconstructing a Menstrual Lodge in the Interior Northwest

This project considered the deposition history of a burned structure located on the Kalispel Tribe of Indians ancestral lands at the Flying Goose site in northeastern Washington. Excavation of the structure revealed stratified deposits that do not conform to established Columbia Plateau architectural types. The small size, location, and absence of artifacts lead us to hypothesize that this site was once a non-domestic structure. We tested this hypothesis with paleoethnobotanical, bulk geoarchaeological, thin section, and experimental firing data to deduce the structural remains and the post-occupation sequence. The structure burned at a relatively low temperature, was buried soon afterward with imported rubified sediment, and was exposed to seasonal river inundation. Subsequently, a second fire consumed a unique assemblage of plant remains. Drawing on recent approaches to structured deposition and historic processes, we incorporate ethnography to argue that this structure was a menstrual lodge. These structures are common in ethnographic descriptions, although no menstrual lodges have been positively identified in the archaeological record of the North American Pacific Northwest. This interpretation is important to understanding the development and time depth of gendered practices of Interior Northwest groups.

Biomolecular archaeology reveals ancient origins of indigenous tobacco smoking in North American Plateau

Chemical analysis of residues contained in the matrix of stone smoking pipes reveal a substantial direct biomolecular record of ancient tobacco (Nicotiana) smoking practices in the North American interior northwest (Plateau), in an area where tobacco was often portrayed as a Euro-American-introduced postcontact trade commodity. Nicotine, a stimulant alkaloid and biomarker for tobacco, was identified via ultra-performance liquid chromatography-mass spectrometry in 8 of 12 analyzed pipes and pipe fragments from five sites in the Columbia River Basin, southeastern Washington State. The specimens date from 1200 cal BP to historic times, confirming the deep time continuity of intoxicant use and indigenous smoking practices in northwestern North America. The results indicate that hunting and gathering communities in the region, including ancestral Nez Perce peoples, established a tobacco smoking complex of wild (indigenous) tobacco well before the main domesticated tobacco (Nicotiana tabacum) was introduced by contact-era fur traders and settlers after the 1790s. This is the longest continuous biomolecular record of ancient tobacco smoking from a single region anywhere in the world-initially during an era of pithouse development, through the late precontact equestrian era, and into the historic period. This contradicts some ethnohistorical data indicating that kinnikinnick, or bearberry (Arctostaphylos uva-ursi) was the primary precontact smoke plant in the study area. Early use likely involved the management and cultivation of indigenous tobaccos (Nicotiana quadrivalvis or Nicotiana attenuata), species that are today exceedingly rare in the region and seem to have been abandoned as smoke plants after the entry of trade tobacco.

Influence of landscape structure, topography, and forest type on spatial variation in historical fire regimes, Central Oregon, USA

In the interior Northwest, debate over restoring mixed-conifer forests after a century of fire exclusion is hampered by poor understanding of the pattern and causes of spatial variation in historical fire regimes. To identify the roles of topography, landscape structure, and forest type in driving spatial variation in historical fire regimes in mixed-conifer forests of central Oregon. We used tree rings to reconstruct multicentury fire and forest histories at 105 plots over 10,393 ha. We classified fire regimes into four types and assessed whether they varied with topography, the location of fuel-limited pumice basins that inhibit fire spread, and an updated classification of forest type. We identified four fire-regime types and six forest types. Although surface fires were frequent and often extensive, severe fires were rare in all four types. Fire regimes varied with some aspects of topography (elevation), but not others (slope or aspect) and with the distribution of pumice basins. Fire regimes did not strictly co-vary with mixed-conifer forest types. Our work reveals the persistent influence of landscape structure on spatial variation in historical fire regimes and can help inform discussions about appropriate restoration of fire-excluded forests in the interior Northwest. Where the goal is to restore historical fire regimes at landscape scales, managers may want to consider the influence of topoedaphic and vegetation patch types that could affect fire spread and ignition frequency.

Kinematic evidence for the effect of changing plate boundary conditions on the tectonics of the northern U.S. Rockies

AbstractWe derive surface velocities from GPS sites in the interior Northwest U.S. relative to a fixed North American reference frame to investigate surface tectonic kinematics from the Snake River Plain (SRP) to the Canadian border. The Centennial Tectonic Belt (CTB) on the northern margin of the SRP exhibits west directed extensional velocity gradients and strain distributions similar to the main Basin and Range Province (BRP) suggesting that the CTB is part of the BRP. North of the CTB, however, the vergence of velocities relative to North America switches from westward to eastward along with a concomitant rotation of the principal stress axes based on available seismic focal mechanisms, revealing paired extension in the northern Rockies and shortening across the Rocky Mountain Front. This change in orientation of surface velocities suggests that the change in the boundary conditions on the western margin of North America influences the direction of gravitational collapse of Laramide thickened crust. Throughout the study region, fault slip rate estimates calculated from the new geodetic velocity field are consistently larger than previously reported fault slip rates determined from limited geomorphic and paleoseismic studies.

Variability of Cloudiness over Mountain Terrain in the Western United States

Abstract This study investigates the spatial and temporal variability of cloudiness across mountain zones in the western United States. Daily average cloud albedo is derived from a 19-yr series (1996–2014) of half-hourly Geostationary Operational Environmental Satellite (GOES) images. During springtime when incident radiation is active in driving snowmelt–runoff processes, the magnitude of daily cloud variations can exceed 50% of long-term averages. Even when aggregated over 3-month periods, cloud albedo varies by ±10% of long-term averages in many locations. Rotated empirical orthogonal functions (REOFs) of daily cloud albedo anomalies over high-elevation regions of the western conterminous United States identify distinct regional patterns, wherein the first five REOFs account for ~67% of the total variance. REOF1 is centered over Northern California and Oregon and is pronounced between November and March. REOF2 is centered over the interior northwest and is accentuated between March and July. Each of the REOF/rotated principal components (RPC) modes associates with anomalous large-scale atmospheric circulation patterns and one or more large-scale teleconnection indices (Arctic Oscillation, Niño-3.4, and Pacific–North American), which helps to explain why anomalous cloudiness patterns take on regional spatial scales and contain substantial variability over seasonal time scales.

Social preferences for invasive plant management: A case Study from the interior Northwest of the United States

Social preferences for invasive plant management: A case Study from the interior Northwest of the United States

Disease suppression in winter wheat from novel symbiosis with forest fungi

Abstract In the Pacific Northwest, USA, pathogenic Fusarium spp. are common in agricultural soils but rare in forest soils. We hypothesized that regional forest soils possess indigenous Fusarium- suppressive microbes, which may enter into novel associations with introduced crop plants, potentially contributing to suppressive soils. To test this hypothesis, we inoculated winter wheat with regional forest litter microbial communities and rhizosphere fungi and challenged plants with pathogenic Fusarium culmorum from regional agricultural fields. We also challenged plants with drought and low-temperature stress, which may augment disease severity. A forest litter microbiome improved survival of Fusarium -infected wheat three-fold and increased growth by 67%. Seedlings inoculated with individual forest fungi developed larger root systems during vernalization. Penicillium sp. doubled yield of Fusarium -infected winter wheat exposed to drought conditions. Indigenous microbes from native plant communities of the interior Northwest mitigate abiotic stresses and may contribute to suppression of a soil-borne wheat disease via novel symbioses.

Linking Agricultural Landowners with Payments for Ecosystem Services in the Interior Northwest: Resources for Extension

Linking Agricultural Landowners with Payments for Ecosystem Services in the Interior Northwest: Resources for Extension

Regional heat safety thresholds for athletics in the contiguous United States

Exertional heat illnesses affect thousands of athletes each year across the United States (U.S.). Heat safety guidelines such as those developed by the American College of Sports Medicine (ACSM) are widely used to direct activities based on environmental conditions but rely on a uniform set of heat safety categories. Due to geographic variations in heat exposure and acclimatization, however, lower heat safety thresholds may be needed in areas with cooler climates. Our study addresses this shortcoming by developing regional guidelines for athletic activity that use relative thresholds of a commonly used heat metric -- the wet bulb globe temperature (WBGT). We employed a unique WBGT climatology for the contiguous U.S. to determine locally extreme WBGTs, defined as the 90th percentile warm season daily maximum value, for 217 stations. Three heat safety regions were identified based on local extremes: Category 3 (WBGTs ≥ 32.3 °C), Category 2 (30.1–32.2 °C), and Category 1 (≤30 °C). Geographically, Category 3 encompasses much of the southeastern quadrant of the U.S. along with portions of the Southwest, and the Central Valley of California; Category 2 areas extend in an arc from the interior Northwest through Nevada and portions of the Midwest, Ohio Valley, and Northeast; and Category 1 locations include the Pacific Coast, New England, and the northern tier of the country. Associated regional activity guidelines based on those developed by the ACSM and the Georgia High School Association (GHSA) were developed for each heat safety region.

Integrating Recent Land Cover Mapping Efforts to Update the National Gap Analysis Program's Species Habitat Map

Abstract. Over the past decade, great progress has been made to develop national extent land cover mapping products to address natural resource issues. One of the core products of the GAP Program is range-wide species distribution models for nearly 2000 terrestrial vertebrate species in the U.S. We rely on deductive modeling of habitat affinities using these products to create models of habitat availability. That approach requires that we have a thematically rich and ecologically meaningful map legend to support the modeling effort. In this work, we tested the integration of the Multi-Resolution Landscape Characterization Consortium's National Land Cover Database 2011 and LANDFIRE's Disturbance Products to update the 2001 National GAP Vegetation Dataset to reflect 2011 conditions. The revised product can then be used to update the species models. We tested the update approach in three geographic areas (Northeast, Southeast, and Interior Northwest). We used the NLCD product to identify areas where the cover type mapped in 2011 was different from what was in the 2001 land cover map. We used Google Earth and ArcGIS base maps as reference imagery in order to label areas identified as "changed" to the appropriate class from our map legend. Areas mapped as urban or water in the 2011 NLCD map that were mapped differently in the 2001 GAP map were accepted without further validation and recoded to the corresponding GAP class. We used LANDFIRE's Disturbance products to identify changes that are the result of recent disturbance and to inform the reassignment of areas to their updated thematic label. We ran species habitat models for three species including Lewis's Woodpecker (Melanerpes lewis) and the White-tailed Jack Rabbit (Lepus townsendii) and Brown Headed nuthatch (Sitta pusilla). For each of three vertebrate species we found important differences in the amount and location of suitable habitat between the 2001 and 2011 habitat maps. Specifically, Brown headed nuthatch habitat in 2011 was −14% of the 2001 modeled habitat, whereas Lewis's Woodpecker increased by 4%. The white-tailed jack rabbit (Lepus townsendii) had a net change of −1% (11% decline, 10% gain). For that species we found the updates related to opening of forest due to burning and regenerating shrubs following harvest to be the locally important main transitions. In the Southeast updates related to timber management and urbanization are locally important.

Climatological Characteristics of Atmospheric Rivers and Their Inland Penetration over the Western United States

Abstract Narrow corridors of water vapor transport known as atmospheric rivers (ARs) contribute to extreme precipitation and flooding along the West Coast of the United States, but knowledge of their influence over the interior is limited. Here, the authors use Interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) data, Climate Prediction Center (CPC) precipitation analyses, and Snowpack Telemetry (SNOTEL) observations to describe the characteristics of cool-season (November–April) ARs over the western United States. It is shown that AR frequency and duration exhibit a maximum along the Oregon–Washington coast, a strong transition zone upwind (west) of and over the Cascade–Sierra ranges, and a broad minimum that extends from the “high” Sierra south of Lake Tahoe eastward across the central Great Basin and into the deep interior. East of the Cascade–Sierra ranges, AR frequency and duration are largest over the interior northwest, while AR duration is large compared to AR frequency over the interior southwest. The fractions of cool-season precipitation and top-decile 24-h precipitation events attributable to ARs are largest over and west of the Cascade–Sierra ranges. Farther east, these fractions are largest over the northwest and southwest interior, with distinctly different large-scale patterns and AR orientations enabling AR penetration into each of these regions. In contrast, AR-related precipitation over the Great Basin east of the high Sierra is rare. These results indicate that water vapor depletion over major topographic barriers is a key contributor to AR decay, with ARs playing a more prominent role in the inland precipitation climatology where lower or less continuous topography facilitates the inland penetration of ARs.

A Pilot Application of Regional Scale Risk Assessment to the Forestry Management of the Upper Grande Ronde Watershed, Oregon

ABSTRACT An issue in forestry management has been the integration of a variety of different information into a threat analysis or risk assessment. In this instance, regional scale risk assessment was applied to the Upper Grande Ronde watershed in eastern Oregon to examine the potential of risk assessment for use in the management of broad landscapes. The site was a focus of study for the U.S. Forest Service through the Interior Northwest Landscape Analysis System (INLAS) project. In the study, a range of stressors, habitats, and endpoints were identified from previous studies in the watershed, and endpoints were determined from meeting with the primary stakeholder, the U.S. Forest Service. These endpoints were focused around the historic range of variability (HRV) defined for the area. The relative risk model (RRM) incorporating a Monte Carlo analysis was used as the analysis tool. The risk model output showed the HRV fire regime was the endpoint most at risk. The results of this analysis were compared to the Wallowa-Whitman National Forest prioritization of watershed restoration analysis. The RRM demonstrated similar results but with a better accounting for uncertainty. From this trial the RRM has proven to be a potential management tool for forestry management.

Mapping a Values Typology in Three Counties of the Interior Northwest, USA: Scale, Geographic Associations Among Values, and the Use of Intensity Weights

Spatial attribution mapping is one method of eliciting the relationship between people and place. I use a landscape values typology and environmental values theory to investigate how people attribute values to the landscape in three counties of Idaho and Oregon. Using geographically referenced values data collected in a mail survey (n = 767), I examine the use of intensity weights when implementing a mapping exercise and the spatial scale and geographic associations between values in the typology. The results demonstrate that places within a landscape can offer multiple values, and that when geographically operationalized the landscape values typology can be divided primarily into two categories: material (socioeconomic quality) and postmaterial (personal/environmental quality) values. The findings reflect the linkages between spatially operationalized values and established environmental values theory, and the need for land use planners, natural resource managers, and local decision makers to facilitate both material and postmaterial values in their decisions.

Coupling tree-ring 13C and 15N to test the effect of fertilization on mature Douglas-fir (Pseudotsuga menziesii var. glauca) stands across the Interior northwest, USA

Nitrogen (N) fertilization causes long-term increases in biomass production in many N-limited forests around the world, but the mechanistic basis underlying the increase is often unclear. One possibility, especially in summer-dry climates, is that N fertilization increases the efficiency with which a finite water supply is consumed to support photosynthesis. This increase is achieved by a reduction in the canopy-integrated concentration of internal CO(2) and thus discrimination against (13)C. We used stable isotopes of carbon (delta(13)C) in tree rings to experimentally test the physiological impact of N fertilization on mature Douglas-fir (Pseudotsuga menziesii Franco var. glauca) stands across the geographic extent of the Intermountain West, USA. The concentration and the stable isotopes of N (delta(15)N) in tree rings were also used to assess the presence and activity of fertilizer N. We hypothesized that N fertilization would (i) increase delta(15)N and N concentration of stemwood relative to non-fertilized stands and (ii) increase stemwood delta(13)C as photosynthetic gas exchange responded to the additional N. This experiment included two rates of urea addition, 178 kg ha(-1) (low) and 357 kg ha(-1) (high), which were applied twice over a 6-year interval bracketed by the 18 years of wood production measured in this study. Foliar N concentrations measured the year after each fertilization treatment suggest that the fertilizer N had been assimilated by the trees (P < 0.001). The N fertilization significantly enriched stemwood delta(15)N by 1.3 per thousand at the low fertilization rate and by 2.4 per thousand at the high rate (P < 0.001) despite variation in soil N between sites. However, we found no significant effect of the N fertilizer on delta(13)C of the annual rings (P = 0.76). These data lead us to suggest that alternative mechanisms underlie the growth response to fertilizer, i.e., increase in canopy area and shifts in biomass allocation.

The fire stones carry: Ethnographic records and archaeological expectations for hot-rock cookery in western North America

Ethnographic data from Kalispel elders in the 1930s attest to use of wild root foods, rock-filled earth ovens, steaming and boiling pits, and hot-rock griddles during the 1800s in forested montane regions of the interior Northwest. Cabeza de Vaca’s narrative of his 1528–1536 travels across the Gulf Coastal Plain of Texas and deserts of northern Mexico illustrates the importance of root foods, earth ovens, and stone boiling in aboriginal Southwest North America. These and other accounts, results of actualistic experiments, and knowledge of cooking requirements afford reliable bases for generating archaeological expectations about fire-cracked-rock assemblages representative of diverse cook-stone facilities.

The Interior Northwest Landscape Analysis System: A step toward understanding integrated landscape analysis

The Interior Northwest Landscape Analysis System (INLAS) project demonstrated a method for assembling teams of scientists to conduct integrated landscape analyses at the mid- or subbasin scale in the interior Northwestern United States. A state and transition modeling system (STM) with transition probabilities calibrated by using a stand-level silvicultural model to estimate rates of vegetative change was used as a central vegetative “modeling engine.” It connected to a variety of resource-related models including: wildlife habitat quantity, insect activity, grazing by ungulates, timber management, and wood utilization potential. Where appropriate, the study team examined other vegetation modeling approaches including an optimization approach based on heuristic methods and modifications to an existing stand-level projection tool, which was integrated with existing fire and insect behavior models. The STM approach provided a relatively simple interface for most resource models. These were connected to examine the influence of vegetative succession, natural disturbances, and management over a 100–200-year horizon under three management scenarios: (1) background natural disturbance, (2) fire suppression only, and (3) active fuel management. Taken all together, the results suggest to us: (1) maintaining abundant large-tree multistoried structure in cool, moist forest conditions is likely to be difficult, (2) both active fuel treatment and passive management scenarios increased the proportion of large-tree single-story forests in dry forest conditions, and (3) fire suppression only was least effective in producing and maintaining these “legacy” structures in either dry or moist forest conditions.

Modeling forest and range land development in rural locations, with examples from eastern Oregon

The risks that wildfires pose for homes and other structures are a major concern of public lands policy and management. Development of private forest and range lands also can have landscape-level implications for public lands, if accompanying changes in private forest owner behavior effect changes in ecological conditions and processes and in wildfire. We characterized the spatial distribution of forest and range land development in three regions of eastern Oregon, USA, including the Interior Northwest Landscape Analysis System (INLAS) study area, to facilitate examining forest and fuel management alternatives to address wildfire and other forest health issues. We developed empirical models describing the spatial distribution of buildings and the construction of new buildings in each region, as a function of population, existing building densities, slope, elevation, and land-use zoning. We used the empirical models to create geographic information system maps of predicted future building densities on forest and range lands to support vegetation, wildfire, and terrestrial and aquatic habitat analyses. Model predictions suggest that future forest and range land development could be relatively limited within the INLAS study area. The results raise conceptual and methodological questions about how best to anticipate future development in rural locations beyond examining and projecting historical trends alone.

A density-dependent stand-level optimization approach for deriving management prescriptions for interior northwest (USA) landscapes

Stand-level forest management prescriptions for federal forests in the interior northwest (USA) have changed emphasis in the past decade from being influenced by economic criteria to being influenced by ecological criteria. The design of forest management prescriptions that maintain stand density levels within a target range is now preferred over the design of prescriptions that maximize net present value. We describe a stand-level optimization process for developing efficient management regimes that uses dynamic programming and a region-limited search strategy. The process develops management regimes by penalizing deviations from a preferred range of stand density. Operational considerations, such as minimum harvest levels, can be important, and are considered as constraints in this modeling process. The timing of harvests is such that entries are only permitted when a minimum harvest can be obtained, when a minimum residual basal area can be maintained, and when harvests are limited to trees with a certain diameter range. Lists of residual, harvested, and dead tree records are available for each decade of the optimal regime. These records of information can facilitate further forest product or habitat suitability analysis associated with forest policy analyses.