Treesearch

Non-native invasive plant species (NNIPS) pose a serious socio-ecological challenge due to their potential to replace and damage critical human-sustaining ecosystems (OTA 1993; Mack et al. 2000; Pimentel 2002). The impacts of non-native species are widespread and significant - altering ecosystem structure and function, threatening other species, and imposing human economic and cultural costs (Mack et al. 2000; Pfeiffer and Voeks 2008). In an increasingly globalized and human-dominated world, species from different bioregions are mixing at increasing rates through the opening of new...

Big sagebrush is an essential component of shrub-steppe ecosystems that is rapidly disappearing from the landscape. Recognizing this, it has become a target of restoration; however, current efforts using direct seeding have shown variable success and planting seedlings may provide a better option. Nonetheless, limited information is available on the nursery production of big sagebrush seedlings. This thesis aims to 1) further refine the cold storage component of sagebrush seedling nursery culture, and 2) investigate seed source variation in Wyoming big sagebrush (Artemisia tridentata ssp....

Douglas' dustymaiden, Chaenactis douglasii (Hook.) Hook. & Arn., is a widespread, inconspicuous, short-lived perennial wildflower that blooms in early summer and is found in basin sagesteppe to upper montane areas throughout the U.S. Intermountain West. The species is proving practical to grow for seed and is expected to be used for western rangeland rehabilitation. Through manual pollination experiments, C. douglasii was found to be only weakly self-fertile; 15% of flowers from geitonogamy and autogamy treatments yielded filled achenes. In contrast, 57% of outcrossed flowers produced...

Species distribution models for 147 bird species have been derived using climate, elevation, and distribution of current tree species as potential predictors (Matthews et al. 2011). In this case study, a risk matrix was developed for two bird species (fig. A2-5), with projected change in bird habitat (the x axis) based on models of changing suitable habitat resulting from changing climate and tree species habitat. Risk was evaluated for three time steps (2040, 2070, 2100) and based on two climate models and two emission scenarios (Hadhi vs. PCMlo).

Phyllolobium, a recently established genus from subgenus Pogonophace of Astragalus, contains about 20 species and four sections, mostly endemic to the Qinghai-Tibetan Plateau (QTP). The uplift of the QTP undoubtedly affected organismic evolution in the region, but further molecular dating in a phylogenetic context is required to test whether diversification is linked in particular to the intense uplift 3.6 million years ago (Ma).

Wildfire management involves significant complexity and uncertainty, requiring simultaneous consideration of multiple, non-commensurate objectives. This paper investigates the tradeoffs fire managers are willing to make among these objectives using a choice experiment methodology that provides three key advancements relative to previous stated-preference studies directed at understanding fire manager preferences: (1) a more immediate relationship between the instrument employed in measuring preferences and current management practices and operational decision-support systems; (2) an...

Forest restoration and fuel reduction treatments have been widely applied in the western United States with the purpose of reducing the size and intensity of wildfires. However, the low value of small-diameter trees produced from such treatments has partly constrained the ability to treat all the areas identified as being in need of treatments. The objective of this study was to analyze the potential for log sort yards to increase the residual value of forest restoration treatments relative to a standard sort at landing in Ravalli County, Montana. We simulated log handing and transportation...

Forest operations generate large quantities of forest biomass residues that can be used for production of bioenergy and bioproducts. However, a significant portion of recoverable residues are inaccessible to large chip vans, making use financially infeasible. New production systems must be developed to increase productivity and reduce costs to facilitate use of these materials. We present a comparison of two alternative systems to produce biomass fuel (i.e., "hog fuel") from forest residues that are inaccessible to chip vans: (1) forwarding residues in fifth-wheel end-dump trailers to a...

Published research emphasizes rapid downstream export of terrestrial carbon from mountainous headwater rivers, but little work focuses on mechanisms that create carbon storage along these rivers, or on the volume of carbon storage. Here we estimate organic carbon stored in diverse valley types of headwater rivers in Rocky Mountain National Park, CO, USA. We show that low-gradient, broad valley bottoms with old-growth forest or active beaver colonies store the great majority of above- and below-ground carbon. These laterally unconfined valley segments constitute

This study tested the erosion mitigation effectiveness of agricultural straw and two wood-based mulches for four years on decommissioned forest roads. Plots were installed on the loosely consolidated, bare soil to measure sediment production, mulch cover, and plant regrowth. The experimental design was a repeated measures, randomized block on two soil types common in the northern Rocky Mountain area. The control produced the most sediment, while wood strands produced the least during the critical first winter following road decommissioning. Following the first year, there was no statistical...