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With global climate change, drought may become more common in the future (IPCC 2007). Several factors will promote more frequent droughts: earlier snowmelt, higher temperatures and higher variability in precipitation. For ecosystems where the water cycle is dominated by snowmelt, warmer temperatures bring earlier melt (Stewart et al. 2005) and longer, drier snow-free periods (Westerling et al. 2006). Higher temperatures will also increase vapor pressure deficit if evapotranspiration does not also increase. Greater variability in precipitation has two implications for plant water balance:...

Agricultural straw mulch is a commonly applied treatment for protecting resources at risk from runoff and erosion events after wildfires. High-resolution QuickBird satellite imagery was acquired after straw mulch was applied on the 2006 Tripod Fire in Washington. We tested whether the imagery was suitable for remotely assessing the areal coverage of the straw mulch treatment. Straw mulch was easily identified in the imagery because of the distinct spectral signature of the mulch against the burned background. The measured straw cover on the ground was correlated to the modeled cover in the...

The Interior West Forest Inventory and Analysis (IWFIA) Program of the USDA Forest Service, Rocky Mountain Research Station, as part of our National Forest System cooperative inventories, conducted a forest resource inventory on the Clearwater National Forest using a nationally standardized mapped-plot design (for more details see section "Inventory methods"). This report presents the highlights of this 1999 inventory using commonly requested variables and summaries. The data could be summarized in other ways for different purposes (see "For further information" on the inside back cover)....

Baseline data on rates of sediment transport provide useful information on the inherent variability of stream processes and may be used to assess departure in channel form or process from disturbances. In August 2000, wildfire burned portions of the Little Granite Creek watershed near Bondurant, WY where bedload and suspended sediment measurements had been collected during 13 previous runoff seasons. This presented an opportunity to quantify increases in sediment loads associated with a large-scale natural disturbance. The first three years post-fire were warm and dry, with low snowpacks...

The Interior West Forest Inventory and Analysis (IW-FIA) program of the USDA Forest Service collects field data on understory vegetation structure that have broad applications. In IW-FIA one aspect of quality assurance is assessed based on the repeatability of field measurements. The understory vegetation protocol consists of two suites of measurements; (1) the structure by lifeform and (2) the structure for individual species with cover greater than five percent. The measurements of structure by lifeform and species are highly repeatable; however, since species identification is confounded...

Wildfire is a common natural disturbance that can influence stream ecosystems. Of particular concern are increases in water temperature during and following fires, but studies of these phenomena are uncommon. We examined effects of wildfires in 2000 on maximum water temperature for a suite of second- to fourth-order streams with a range of burn severities in the Bitterroot River basin, Montana. Despite many sites burning at high severity, there were no apparent increases in maximum water temperature during the fires. One month after fire and in the subsequent year, increases in maximum...

Maintaining adequate nutrient supply to maintain or enhance tree vigor and forest growth requires conservation of topsoil and soil organic matter. Sometimes nutrient amendments are also required to supplement inherent nutrient-pool limitations or replenish nutrients removed in harvested material. The goal is to maintain the productive potential of the soil and, when economically feasible and environmentally acceptable, enhance productivity where nutrient supply significantly limits growth. Nitrogen (N) is most frequently the limiting nutrient in Pacific Northwest forests, particularly on...

We found that peat moss, amended with various ratios of pellets comprised of equal proportions of biochar and wood flour, generally had chemical and physical properties suitable for service as a substrate during nursery production of plants. High ratios of pellets to peat (>50%) may be less desirable because of high C:N, high bulk density, swelling associated with water absorption, and low volumetric water content, whereas a mixture of 75% peat and 25% pellets had enhanced hydraulic conductivity and greater water availability at lower (

Studies of postzygotic isolation often involve well-differentiated taxa that show a consistent level of incompatibility, thereby limiting our understanding of the initial stages and development of reproductive barriers. Dendroctonus ponderosae provides an informative system because recent evidence suggests that distant populations produce hybrids with reproductive incompatibilities. Dendroctonus ponderosae shows an isolation-by-distance gene flow pattern allowing us to characterize the evolution of postzygotic isolation (e.g., hybrid inviability, hybrid sterility) by crossing populations...

Wildfire is a major forest disturbance in interior Alaska that can both directly and indirectly alter ecological processes. We used a combination of pre- and post-fire forest floor depths and post-fire ground cover assessments measured in the field, and high-resolution airborne hyperspectral imagery, to map forest floor conditions after the 2004 Taylor Complex in Alaska's boreal forest. We applied a linear spectral unmixing model with five endmembers representing green moss, non-photosynthetic moss, charred moss, ash and soil to reflectance data to produce fractional cover maps. Our study...