Treesearch

Our objective in the present study is to provide basic insights into the coupling between external-gas and solid biomass vegetation processes that control the dynamics of flame spread in wildland fire problems. We focus on a modeling approach that resolves processes occurring at vegetation and flame scales, i.e., the formation of flammable vapors due to the thermal degradation of the solid biomass, the subsequent combustion in ambient air, the thermal feedback to the biomass through radiative and convective heat transfer, and the possible transition from flaming combustion (taking place...

In deconstructing lignocellulosic biomass, processing solvents directly and indirectly influence the process efficiency by reducing recalcitrance, fractionating target components, preserving/modifying biomass components, etc. Hydrotropic solvents have shown effective biomass fractionation performance due to their unique amphiphilic structure. In particular, these hydrotropes effectively separate lignin from the cellulose-rich fraction with minimum modification and maximum recovery, which aligns well with the biorefinery strategy by enhancing the recovered lignin quality and quantity....

Quantifying the dynamics of natural populations is a central issue in ecology. In the Pacific Northwest of North America, climate extremes are becoming more frequent and severe with projections of increasing winter floods and prolonged droughts during summer. Using a 13-year dataset of adult (Age 1+) Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii), we evaluated the effects of three droughts on annual growth and condition in two stream reaches of Mack Creek, H.J. Andrews Experimental Forest, Oregon, USA. In the three drought years, the onset of seasonal low flow consistently started...

Accurate measurements of particle diameter are necessary for quantitative characterization of key aerosol properties including the Cunningham slip correction factor, charging probability, diffusion coefficient, coagulation coefficient, and optical properties. In this study, we use four techniques to measure the diameter of nominal 100 nm reference spheres having a distributional standard deviation of less than 2 nm. The instruments used are a differential mobility analyzer (DMA), atomic force microscopy (AFM), scanning electron microscopy (SEM), and an electrical-gravitational aerosol...

The transition from Late Pleistocene to Holocene climates triggered biogeographical upheavals worldwide that included species’ range shifts, changes in community composition and structure, altered disturbance regimes, and development of new ecological interactions. The Great Basin, with its hundreds of high mountain ranges interspersed by broad basins, was a prominent stage on which such dynamics unfolded. Many plant and animal species remained scattered at low elevations throughout the Great Basin during the cold Late Pleistocene. Without significant displacements in latitude, they...

Conservationists increasingly position conservation that is mutually beneficial to people and biodiversity on the promise of empowerment of people through participatory discourse, metrics, processes, and outcomes. Empowerment represents multidimensional concepts and theories that permeate the interlinking levels of power, from the psychological to the political, and social scales in which conservation operates. The multifaceted nature of empowerment makes it challenging to understand, pursue, and evaluate as a central philosophical commitment and goal-oriented practice in conservation....

Timber was a significant economic driver in many rural communities of the Pacific Northwest throughout much of the 20th century. However, the number of timber-related jobs began declining in the 1980s, leading to hardship in many timber-dependent communities. Since then, some state and local public officials have become interested in promoting forest-based tourism to boost local economies. Jeff Kline, a research forester and economist with the USDA Forest Service Pacific Northwest Research Station, and Ian Munanura, a tourism expert and associate professor at Oregon State University,...

Background: For at least four decades, practitioners have recognized advantages of aerial versus ground ignition for maximizing the effectiveness of prescribed fires. For example, larger areas can be ignited in less time, or ignition energy may be variously targeted over an area in accordance with the uneven distribution of fuels. The maturation of wireless communication, geopositioning systems, and unmanned aerial systems (UAS) has enhanced those advantages, and UAS approaches also provide further advantages relative to helicopter ignitions, such as reduced risk to human safety, lower...

Increased understanding of how mechanical thinning, prescribed burning, and wildfire affect subsequent wildfire severity is urgently needed as people and forests face a growing wildfire crisis. In response, we reviewed scientific literature for the US West and completed a meta-analysis that answered three questions: (1) How much do treatments reduce wildfire severity within treated areas? (2) How do the effects vary with treatment type, treatment age, and forest type? (3) How does fire weather moderate the effects of treatments? We found overwhelming evidence that mechanical thinning with...

Producing cross-laminated timber (CLT) has opened a new market for the lumber industry in North America, while few hardwood species have been studied in the U.S. for CLT production. Combining hardwood species in mixed hardwood CLT or in hybrid CLT can be a solution to boost the market of the undervalued hardwoods. However, the knowledge gap on bonding hardwoods needs to be filled to provide evidence of feasibility. This study focused on the face bonding properties of the cross laminations made of seven hardwood species and two softwood species from the Great Lakes region using two commercia...