Treesearch

Multiple climate change vulnerability assessments in the Pacific Northwest region of the USA provide the scientific information needed to begin adaptation in forested landscapes. Adaptation options developed by resource managers in conjunction with these assessments, newly summarized in the Climate Change Adaptation Library of the Western United States, provide an extensive choice of peer-reviewed climate-smart management strategies and tactics. More adaptation options are available for vegetation than for any other resource category, allowing vegetation management to be applied across a...

Swiss needle cast (SNC) is a Douglas-fir foliage disease caused by the fungus Phaeocryptopus gaeumannii Rohde (Petrak). The spore-bearing structures of this fungus (pseudothecia) occlude the stomata in Douglas-fir needles resulting in an inhibition of gas exchange and photosynthesis, premature foliage loss, and reduced growth (Hansen et al., 2000; Manter et al., 2000). The volume growth reductions inflicted by SNC can exceed 50% in severely diseased stands (Maguire et al., 2011). Since the 1990s, the disease has continued to intensify in coastal low-elevation forests in the Pacific...

Accurate forest inventory is of great economic importance to optimize the entire supply chain management in pulp and paper companies. The aim of this study was to estimate stand dominate and mean heights (HD and HM) and tree density (TD) of Pinus taeda plantations located in South Brazil using in-situ measurements, airborne Light Detection and Ranging (LiDAR) data and the non- k-nearest neighbor (k- NN) imputation. Forest inventory attributes and LiDAR derived metrics were calculated at 53 regular sample plots and we used imputation models to retrieve the forest attributes at plot and...

The term “load bridging” describes a phenomenon in which the physical interaction between various packaging components acts as a series of discrete loads in a given unit load and adds stiffness to the shipping pallet/load combination. Current pallet design practices often ignore the aspect of load bridging and assume that the pallet payload is flexible and uniformly distributed over the pallet surface. This can influence the load‐carrying capacity of the pallet. The study reported in this paper investigated the relationship between the stretch wrap containment force and load bridging in...

Using 27 years of point count data collected at the San Joaquin Experimental Range, Madera County, California, we modeled the importance of weather and climate variables on annual variability in the abundance of 35 bird species, to assess the potential responses of birds to changing environmental conditions. We used semi-parametric Poisson generalized additive models (GAM) with smoothing functions to explore relationships between bird abundance and the independent climatic and weather variables and to extract the best parametric polynomial model. We then selected among three parametric...

Dead woody material (DWM) plays numerous important roles in forest ecosystems; however, through the process of decomposition, it undergoes structural and chemical changes that progressively alter its function in these roles. Much remains unknown about how DWM mechanical strength and structural integrity change through decomposition in natural forest settings. We assessed changes in wood strength (bending strength, compressive strength, and surface hardness) using standard wood stakes of known initial mass from three species. The stakes were placed in forested settings for two and four...

Macroinvertebrate community taxonomic and trait structure showed consistent differences between riffles and pools across 12 headwater streams in the Sierra Nevada (California) even as flows varied from wet to dry years and between seasons. Densities of Ephemeroptera, Plecoptera, Trichoptera, Elmidae, Orthocladiinae and Diamesinae midges, and mites were greater in riffles, whereas Tanypodinae, Chironominae, Sialis, and Pisidiumwere more abundant in pools. Pools had higher densities but estimated biomass was greater in riffles. Collector-gatherer and micropredator abundances were greater in...

Bolted/pinned joints in orthotropic composite materials have received considerable attention over the years. Bolt fastening is one of the most commonly used methods to connect wood to wood and/or wood to steel, etc. Stresses at such connections can be the “Achilles’ heel”, causing structural failures. Notwithstanding the challenges in stress analyzing bolted joints, their advantages and widespread use motivate developing ability to optimize their design. Acknowledging the above, a finite element code is combined here with a screening optimization algorithm to optimize a bolt-hole pattern...

The frequently observed forest decline in water-limited regions may be associated with impaired tree hydraulics, but the precise physiological mechanisms remain poorly understood. We compared hydraulic architecture of Mongolian pine (Pinus sylvestris var. mongolica) trees of different size classes from a plantation and a natural forest site to test whether greater hydraulic limitation with increasing size plays an important role in tree decline observed in the more water-limited plantation site. We found that trees from plantations overall showed significantly lower stem hydraulic efficienc...

Native bees are declining worldwide, but conserving or restoring their habitat requires a better understanding of bee-flower associations. High quality bee habitat includes flowers that provide pollen and nectar preferred by bees. However, little data exist about which plants are commonly used by bees in the Pacific Northwest, or whether bees prefer certain plant characteristics over others. We examined bee and plant communities in an Oregon riparian ecosystem. Our purpose was to describe bee-plant associations, determine which plants are most frequently visited by bees, identify plants...