Treesearch

This report highlights significant research findings and accomplishments of the Pacific Northwest Research Station during fiscal year 2017.

Laboratory and field experiments focused on pyrolysis and ignition coupled with sufficient description of fuel characteristics and physics-based modeling are being used to improve our understanding of combustion processes in mixed (heterogeneous) fuel beds managed with prescribed fire in the southern United States. Previous pyrolysis work has typically used ground-up samples, thus eliminating any effects caused by moisture content, fuel particle shape, or heating mode. We are measuring pyrolysis at bench, laboratory and field-scale using intact fuels from living plants. Pyrolysis products...

The majority of environmental DNA (eDNA) assays for vertebrate species are based on commonly analyzed regions of the mitochondrial genome. However, the high degree of mitochondrial similarity between two species of charr (Salvelinus spp.), southern Dolly Varden (S. malma lordii) and bull trout (Salvelinus confluentus), precludes the development of a mitochondrial eDNA assay to distinguish them. Presented here is an eDNA assay to detect bull trout based on the first ribosomal internal transcribed spacer (ITSI), a nuclear marker. This assay successfully detects bull trout and avoids detecting...

The NHERI TallWood project is a U.S. National Science Foundation-funded four-year research project focusing on the development of a resilient tall wood building design philosophy. One of the first major tasks within the project was to test a full-scale two-story mass timber building at the largest shake table in the U.S., the NHERI@UCSD’s outdoor shake table facility, to study the dynamic behaviour of a mass timber building with a resilient rocking wall system. The specimen consisted of two coupled two-story tall post-tensioned cross laminated timber rocking walls surrounded by mass timber...

The collective U.S. housing market was primarily positive in May 2018, on month-over-month and year-over-year bases. New single-family permits declined on a monthly basis. Existing house sales and multifamily permits were negative on month-over-month and year-over-year bases. Regionally, data were mixed across all sectors.

The collective U.S. housing market was primarily negative in June 2018, on month-over-month and year-over-year bases. New single-family (SF) house starts, under construction, completions, and SF sales were negative on a monthly basis. Existing house sales were negative on month-over-month and year-over-year bases. Regionally, data were mixed across all sectors.

This study examined in detail the utility and validity of water retention value (WRV) for characterizing the extent of fibrillation of micro and nanofibrils. A bleached pulp fiber sample was either refined to different degrees using a PFI mill or milled for different time periods using a SuperMassColloider (SMC), to produce micro and nanofibril samples. These fibril samples were then characterized by electronic microscopic imaging (SEM and TEM), degree of polymerization (DP), Canadian Standard Freeness (CSF), enzymatic adsorption (EA), enzymatic cellulose digestibility (ED), as well as WRV...

The USDA National Agricultural Library (NAL) maintains the Life Cycle Assessment (LCA) Commons, an open-access data repository. The LCA Commons supports the Federal LCA research community to advance LCA research through collaboration on matters of data transfer and access. NAL and USDA Forest Service (USFS) are collaborating to develop a consistent and repeatable workflow to systematically provide public access to life-cycle inventory (LCI) data for forestry and forest-based products. The workflow, which includes modeling, format conversion, and publication through the LCA Commons, must be...

This study investigates the interannual variability of wind energy resources across China and how it changes with season by applying empirical orthogonal function (EOF) analyses to gridded wind data from the Climate Forecast System Reanalysis (CFSR) from January 1979 through December 2011. The first EOF mode (EOF1) represents between 22% variance for winter and 29% for summer. Spatially, the variation is largely consistent across China for summer and autumn and almost opposite between north and south for spring and winter, and the strongest variation in all seasons is found over Inner...

The arrival and spread of emerald ash borer (EAB) across the western Great Lakes region has shifted considerable focus towards developing silvicultural strategies that minimize the impacts of this invasive insect on the structure and functioning of black ash (Fraxinus nigra) wetlands. Early experience with clearcutting in these forests highlighted the risks of losing ash to EAB from these ecosystems, with stands often retrogressing to marsh-like conditions with limited tree cover. Given these experiences and an urgency for increasing resilience to EAB, research efforts began in north-centra...