Treesearch

Pacific martens (Martes caurina humboldtensis) in coastal forests of Oregon and northern California in the United States are rare and geographically isolated, prompting a petition for listing under the Endangered Species Act. If listed, regulations have the potential to influence land-use decisions on public and private lands, but no estimates of population size, density, or viability of remnant marten populations are available for evaluating their conservation status. We used GPS and VHF telemetry and spatial mark-resight to estimate home ranges, density, and population size of Pacific...

Humans alter landscapes and native species distributions in many ways, including alterations mediated via domestic pets. While the negative impacts of domestic cats are well documented worldwide, the ecological effects of domestic dogs have received less scientific attention, particularly in the United States. Prevalence of free-ranging dogs may be especially problematic in areas with low density, but relatively ubiquitous human populations. We used camera-trap data collected during a 2008-2010 landscape-scale study consisting of 1,181 camera stations (357 camera clusters) stratified over...

The paired watershed approach is the most popular tool for quantifying the effects of forest watershed management on water sustainability. But this approach does not often address the critical factor of water stored in the landscape. Future work needs to quantify storage in paired watershed studies to inform sustainable water management.

The fracture properties and toughening mechanisms of cellulose- and cellulose-rubber hybrid-modified epoxy polymers and glass-fibre (GF) composites are investigated. The cellulose modifiers used are microcrystalline cellulose (MCC) and cellulose nanocrystals (CNC), and the rubber modifiers are carboxyl-terminated butadiene-acrylonitrile (CTBN) and core-shell rubber (CSR). The toughening mechanisms of the MCC-epoxy and CNC-epoxy were identified to be crack deflection, shear band yielding, particle rupture or pull-out and debonding of the cellulose particles, which was followed by plastic...

The fate of live forest biomass is largely controlled by growth and disturbance processes, both natural and anthropogenic. Thus, biomass monitoring strategies must characterize both the biomass of the forests at a given point in time and the dynamic processes that change it. Here, we describe and test an empirical monitoring system designed to meet those needs. Our system uses a mix of field data, statistical modeling, remotely-sensed time-series imagery, and small-footprint lidar data to build and evaluate maps of forest biomass. It ascribes biomass change to specific change agents, and...

The vast extent and inaccessibility of boreal forest ecosystems are barriers to routine monitoring of forest structure and composition. In this research, we bridge the scale gap between intensive but sparse plot measurements and extensive remote sensing studies by collecting forest inventory variables at the plot scale using an unmanned aerial vehicle (UAV) and a structure from motion (SfM) approach. At 20 Forest Inventory and Analysis (FIA) subplots in interior Alaska, we acquired overlapping imagery and generated dense, 3D, RGB (red, green, blue) point clouds. We used these data to model...

Lidar provides critical information on the three-dimensional structure of forests. However, collecting wall-towall laser altimetry data at regional and global scales is cost prohibitive. As a result, studies employing lidar for large area estimation typically collect data via strip sampling, leaving large swaths of the forest unmeasured by the instrument. The goal of this research was to develop and examine the performance of a coregionalization modeling approach for combining field measurements, strip samples of airborne lidar and Landsat-based remote sensing products to predict abovegroun...

Forest ecosystems dominated by Tsuga canadensis are undergoing fundamental changes in function and composition from infestations by hemlock woolly adelgid (Adelges tsugae). We proposed that the first step to restoring southern Appalachian riparian forests following T. canadensis mortality would be eliminating the evergreen shrub, Rhododendron maximum. We hypothesized that removing R. maximum would increase light transmittance, soil moisture and temperature; and subsequently, enhance herbaceous-layer diversity and promote tree seedling recruitment and survival. We tested these hypotheses at...

Inbreeding has been difficult to quantify in wild populations because of incomplete parentage information. We applied and extended a recently developed framework for addressing this problem to infer inbreeding rates in Northern Spotted Owls (Strix occidentalis caurina) across the Pacific Northwest, USA. Using pedigrees from 14,187 Northern Spotted Owls, we inferred inbreeding rates for 14 types of matings among relatives that produce pedigree inbreeding coefficients of F=0.25 or F=0.125. Inbreeding was most common in the Washington Cascades, where an estimated 15% of individuals are...

The plants and fungi that are harvested from forests for purposes other than timber are not fully incorporated into management, policies, or resource valuation. These nontimber forest products (NTFPs) have important social, economic, and ecological values and they are integral to the culture of the people of the United States. The plants and fungi are fundamental to the functioning of healthy forests and are essential for the resilience of these ecosystems.