Breast-high stem sections were sampled from 56 western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees growing in 15 plots representing a wide range of tree and site conditions in northwestern Oregon. Growth and wood density traits of individual rings were measured via X-ray densitometry, and relationships of ring density and its...
We evaluated effects of chemical fertilizer, spacing, and interplanted nitrogen-fixing trees on wood density and diameter growth of 15-year-old Eucalyptus saligna trees. The trees were grown in silvicultural trials established on former sugarcane land on the island of Hawaii. Elevation was 480 m, slopes were gentle, and annual rainfall averaged...
The Willamette Valley (WV) race of ponderosa pine (Pinus ponderosa) is being widely planted for timber in the Willamette Valley, western Oregon, because it grows in habitats that are either too wet or too dry for Douglas-fir (Pseudotsuga menziesii). Compared to the eastern Cascade Mountains (CM), the WV has 3...
Like most ecological communities, aspen (Populus tremuloides) forests are influenced by a synergy of bottom-up (resources-driven) and top-down (predator-driven) processes. Since the 1920s, ecologists have observed the decline of many aspen communities throughout the Intermountain West. The extent and possible drivers of this decline are topics of much recent scientific...
To learn the effect of wind on a species native to a windy site, I compared germination, seedling survival, seedling form, and the force required to uproot seedlings in a wind-exposed and a wind-sheltered site. In February 1992, the sand dune perennial Lupinus arboreus Sims. was planted in wind-exposed and...
Herein, we posit a link between the ecological extinction of wolves in the American West
and the expansion in distribution, increased abundance, and inflated ecological influence
of coyotes. We investigate the hypothesis that the release of this mesopredator from wolf
suppression across much of the American West is affecting, via...
To guide the future development of CO₂-atmospheric inversion modeling systems, we analyzed the errors arising from prior information about terrestrial ecosystem fluxes. We compared the surface fluxes calculated by a process-based terrestrial ecosystem model with daily averages of CO₂ flux measurements at 156 sites across the world in the FLUXNET...
Recent natural disasters around the world including
both tsunamis and hurricanes, have highlighted the inability
of wood buildings to withstand wave and surge
loading during these extreme events. Little is known
about the interaction between coastal residential light-frame
wood buildings and wave and surge loading because
often little is left...
Wood-plastic composites are generally presumed to be inherently more resistant to moisture uptake than solid wood, but there is little data on the relative rates of moisture uptake in these materials over time. Trex[R] and Strandex[R] deck sections were immersed in water for up to 215 days, then sections were...
This article examines visitor perceptions of voluntary environmental programs (VEPs) at the Mt. Bachelor ski area in Oregon, USA by examining what they know about VEPs, how these programs influence motivations to visit this area currently and in the future, and how place attachment, value orientations, and specialization influence these...
Six 40-year-old red alders (Alnus rubra Bong.) were harvested from a mixed stand of A. rubra and big-leaf maple (Acer macrophyllum Pursh) in the Oregon Coast Range to evaluate variation in their wood characteristics at two heights. Because the trees had a slight lean (4 to 14°), we sampled along...
The emergence of a new generation of remote sensing and geopositioning technologies, as well as increased capabilities in image processing, computing, and inferential techniques, have enabled the development and implementation of increasingly efficient and cost-effective multilevel sampling designs for forest inventory. In this paper, we (i) describe the conceptual basis...
Lidar is currently the most accurate method for remote estimation of forest structure, but it has limited spatial and temporal coverage. Conversely, Landsat data are more widely available, but exhibit a weaker relationship with structure under medium to high leaf area conditions. One potentially valuable means of enhancing the relationship...
Airborne laser scanning, collected in a sampling mode, has the potential to be a valuable tool for estimating the biomass resources available to support bioenergy production in rural communities of interior Alaska. In this study, we present a methodology for estimating forest biomass over a 201,226-ha area (of which 163,913...
Large quantities of smaller diameter materials are available in the overstocked forests of eastern Oregon and Washington, but the costs of removing these materials and the long distances from markets sharply reduce the potential of this resource. Failure to thin these forests will sharply increase the likelihood of catastrophic wildfires....
In a multilevel study to determine limits to underplanted conifer seedling growth, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), western redcedar (Thuja plicata Donn ex D. Don), and western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings were planted beneath second-growth Douglas-fir stands that had...
Flux estimates show that upward mixing of the deep-water nitrate pool accounts for more than 85% of the total new nitrogen input to the euphotic zone of Crater Lake. Because measured primary productivity (360 mg C m-2 d-1) is 10–30 times higher than a level supported solely by the input...
Retreating glaciers and the periglacial areas they vacate for organismal colonization produce a harsh environment of extreme radiation, nutrient limitations, and temperature oscillations. They provide a model system for studying mechanisms that drive establishment and early assembly of communities. Here, we synthesize more than twenty years of research at the...
The high decay resistance of western redcedar (Thuja plicata Donn) is due to the presence of toxic extractives, called tropolones, in the heartwood. Therefore, tropolone content may be used as an indicator of decay resistance. With increment core-sized samples of western redcedar heartwood, we used gas chromatography to measure tropolone...
When large carnivores are extirpated from ecosystems that evolved with apex predators, these systems can change at the herbivore and plant trophic levels. Such changes across trophic levels are called cascading effects and they are very important to conservation. Studies on the effects of reintroduced wolves in Yellowstone National Park...
Uses of outdoor natural areas, like National Forests in the United States, have been undergoing change. Some changes, including criminal activities and domestic terrorism, may have quite important impacts to outdoor enthusiasts and managers. Activities include some relatively traditional management challenges, like arson and thefts, and newer challenges, such as...
To examine whether stream nitrogen concentrations in forested reference catchments have
changed over time and if patterns were consistent across the USA, we synthesized up to 44 yr
of data collected from 22 catchments at seven USDA Forest Service Experimental Forests.
Trends in stream nitrogen presented high spatial variability both...
The ratio of live crown length to tree height (crown ratio; CR) is often used as an important predictor variable for tree level growth equations, particularly for multi-species and multi-layered stands. Also, CR indicates tree vigour and can be an important habitat variable. Measurement of CR for each tree can...
Both the structure and composition of naturally generated early-seral forests in the Pacific Northwest (PNW) can be profoundly different than that of more developed forest seres, especially in the period after a major disturbance but before conifers re-develop a closed canopy. While it is reasonable to suggest that the unique...
We sought to improve net ecosystem exchange (NEE) estimates for a tall, dense, mature Douglas-Fir forest in the Oregon Coast range characterized by weak flows, systematic wind directional shear, and limited turbulent mixing throughout the diurnal period. We used eddy covariance (EC) observations at two levels and concurrent biological measurements...
The nonexponential phosphorescence decay of a highly folded form of poly-riboadenylic acid (poly rA) with noncovalently bound dye is explained by a novel application of a well-known theory of electronic excitation transfer based on the Förster mechanism. This theory, originally used to describe singlet-singlet energy transfer from donor molecules to...
We analyzed 45 years of data collected from three ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) levels-of-growing-stock installations in Oregon (OR) and northern California (CA), USA, to determine the effect of stand density regimes on stand productivity and mortality. We found that periodic annual increment (PAI)...
Large-scale commercial thinning of young forests in the Pacific Northwest is currently promoted on public lands to accelerate the development of late-seral forest structure for the benefit of wildlife species such as northern spotted owls (Strix occidentalis caurina) and their prey, including the northern flying squirrel (Glaucomys sabrinus). Attempts to...
Background: Management strategies have been proposed to minimise the effects of climate
change on forest resilience.
Aims: We investigated the Pacific Northwest US region forest carbon balance under current
practices, and changes that may result from management practices proposed for the region’s
34 million ha of forests to mitigate climate...
Almost universally, forest inventory and monitoring databases are incomplete, ranging from missing data for only a few records and a few variables, common for small land areas, to missing data for many observations and many variables, common for large land areas. For a wide variety of applications, nearest neighbor (NN)...
High concentrations of the fumigant methylisothiocyanate (MITC) will effectively control decay fungi in large wood structures, but the fungitoxicity of low MITC concentrations and the influence of wood moisture content (MC) on its performance are not well understood. The MC of Douglas-fir heartwood greatly influenced the susceptibility of the decay...
Many protected areas or parks in developing countries have buffer zones at their
boundaries to achieve the dual goals of protecting park resources and providing
resource benefits to neighbouring people. Despite the prevalence of these zoning
policies, few behavioural models of people’s buffer zone use inform the sizing and
management...
Hydrological processes in the humid tropics differ from other regions in having greater energy inputs and faster rates of change, including human-induced change. Human influences on population growth, land use and climate change will profoundly influence tropical hydrology, yet understanding of key hydrological interactions is limited. We propose that efforts...
From 27 June to 3 September 1999, CO2 fluxes from a 5-year-old, 84.15-ha vegetated clearcut in sub-boreal British Columbia were measured using a Bowen ratio energy balance (BREB) system and a second approach (the component model) that was based on scaled up CO2-flux measurements from belowground and plants (spruce seedlings...
Intertemporal timber supply models typically assume perfect capital markets and perfectly inelastic supplies of land. Using a dynamic model of U.S. timber and agriculture markets, we examine (i) borrowing limits or capital constraints, in which investment in forest management on nonindustrial private ownerships is restricted, and (ii) a nonzero elasticity...
Preservative treatment of whole, wood-based composite products (mainly panels) has disadvantages; problems largely stem from swelling, strength loss, and incomplete or inappropriate penetration during treatment, and distortion during redrying. Pretreatment of comminuted wood prior to mat lay-up is one alternative, though the addition of chemicals may affect bonding during subsequent...
Mylone@ and tridipam are two solid chemicals that decompose to produce methylisothiocyanate (MIT), a highly effective wood fumigant. In this study, two techniques -- a rapid, test-tube method and small-scale, wood-block assay -- were used to determine the effect of the pH of various chemical buffers on the decomposition of...
Basal area and height growth were analyzed for individual trees in uneven-aged ponderosa pine (Pinus ponderosa
Dougl. ex Laws.) and lodgepole pine (Pinus contorta Dougl. ex. Loud.) stands in central Oregon. Basal area
growth was modeled as a function of other stand and tree variables to address three general objectives:...
Fracture toughness of wood and wood composites has traditionally been characterized by a stress intensity factor, an initiation strain energy release rate (G[subscript init]) or a total energy to fracture (G[subscript f]). These parameters provide incomplete fracture characterization for these materials because the toughness changes as the crack propagates. Thus...
The metabolic theory of ecology (MTE) predicts the effects of body size and temperature on metabolism through considerations of vascular distribution networks and biochemical kinetics. MTE has also been extended to characterise processes from cellular to global levels. MTE has generated both enthusiasm and controversy across a broad range of...
Swiss needle cast, a foliar disease caused by the Ascomycete Phaeocryptopus gaeumannii (T. Rohde) Petr., continues to afflict Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in north coastal Oregon. Permanent plots were installed in 1998 to assess growth impacts and monitor disease severity. Gross periodic annual increment was measured for three 2-year...
The hyporheic zone is of great interest for stream ecologists because of its role in stream biogeochemical processing. Our study addresses the effects of leaf-litter inputs and varying discharge on surface–hyporheic water exchange and their possible consequences for the hyporheic zone biogeochemistry. Our study was conducted during autumn in Riera...
Foresters face new and evolving challenges as society reconsiders the balance of its interests between wood production and the provision of ecosystem services in the management of forests. Whatever paths this process may take, sound and broad-based decisions will continue to require accurate and relevant measurements of current forest conditions...
Gomphus sensu lato (Gomphales) was described to include species of cantharelloid-gomphoid fungi that had 'merulioid' (wrinkled) hymenia and verrucose spores. Gomphus sensu stricto is currently characterized by unipileate to merismatoid (composed of several pilei) basidiomata, depressed funnel- to fan-shaped pilei, presence of clamp connections, and verrucose spores; it has three...
Global sustainability goals have led to the development of the green building movement. The Green
Building Program, stemming from the movement, has had unprecedented success as it provides a quantifi able
metric to people’s efforts towards sustainable development. Sustainable development and green buildings are often
used interchangeably. Although, sustainable development...
The U.S, Forest Service regularly removes tons of dead biomass from federal forestlands to control and prevent devastating wildfires. Every year thinning young trees and brush, as well as removing dead biomass from the forest floor generates large quantities of low-grade woody material for which there is little use. Currently...
Adverse effects on mechanical properties from using a supercritical fluid (SCF) to increase preservative penetration of refractory woods were evaluated by treating small ponderosa pine sapwood specimens with supercritical carbon dioxide at 64 combinations of temperatures (35 to 80 C), pressure (1,000 to 4,000 psig), and time (0.5 to 2...
The effect of supercritical fluid treatment on superficial gas permeability of Douglas-fir was investigated by using carbon dioxide either alone or amended with methanol. Permeability increased in a majority of samples, although nearly one-third of the specimens declined in permeability. Improvements in permeability appeared to be unrelated to variations in...
Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stumps, both healthy and infected by Phellinus weirii (Murr.)Gilbertson, were fumigated with chloropicrin at a clearcut site on Washington s Olympic Peninsula. Vegetation cover on plots adjacent to treated and untreated stumps was evaluated to determine fumigant effects on vascular plants and moss. Ninety-eight vascular...