Treesearch

Diel variations in stream discharge have long been recognized, but are relatively little studied. Here we demonstrate that these diel fluctuations can be used to investigate both streamflow generation and network routing. We treat evapo-transpiration (ET) as a distributed impulse function in an advection model and analyze the effect of ET on diel fluctuations in discharge. We show that flow velocity is high during high baseflow, discharge fluctuations tend to be in phase, and constructive interference reinforces ET-generated signals resulting in strong diel fluctuations measured at a...

This technical note describes consumer preferences within selected demographic categories in two major Pacific Northwest markets for six domestic wood species. These woods were considered for construction of four furniture pieces. Chi-square tests were performed to determine species preferences based on gender, age, and income. Age and income were statistically significant (with a stronger effect for age); gender was not significant. Older respondents preferred oak whereas younger respondents preferred spruce. Cherry was preferred by respondents in higher income categories and oak by...

Research suggests that forest land development can reduce the productivity of remaining forest land because private forest owners reduce their investments in forest management. We developed empirical models describing forest stocking, thinning, harvest, and postharvest tree planting in eastern Oregon, as functions of stand and site characteristics, ownership, and building densities. The models are based on USDA Forest Service Forest Inventory and Analysis data gathered in eastern Oregon in 1987 and 1998, and data describing building densities gathered by the Oregon Department of Forestry...

The implementation of Sustainable Forest Management (SFM) in the United States is strongly influenced by U.S. forest products markets and the numerous management decisions made by individual landowners and managers. These decisions are influenced by a mix of market incentives and regulatory actions reducing predictability in assessing progress towards SFM and causing some proponents of SFM angst because prices might provide insufficient incentive for what they believe are necessary forest practices. At the same time, conservation proponents are advocating forest management regimes that...

Relationships between pressure gradients and flow rates in the xylem are incompletely understood because steady-state conductivity coefficients are inadequate for predicting and interpreting flow under the non-steady-state conditions more prevalent in intact trees. The goal of this study was to determine the magnitude of deviation of trunk sapwood specific conductivity (ks) from that predicted by Darcy's law when ks is measured under steady-state vs. non-steady-state conditions. The results represent very significant deviations from flow rates predicted by Darcy's law, and suggest that if...

We use regionally available digital elevation models and land-cover data, calibrated with ground- and photo-based landslide inventories, to produce spatially distributed estimates of shallow, translational landslide density (number/unit area) for the Oregon Coast Range. We resolve relationships between landslide density and forest cover. We account for topographic variability between sites and landslide detection bias in air-photo mapping. Even so, ratios of landslide density in forest classes differ among sites. We present strategies for subsampling available data to quantify this...

Public land managers are confronted with an ever-growing and diversifying set of demands for providing recreation opportunities. Coupled with a variety of trends (devolution of governance and decisionmaking, population growth, technological innovation, shifts in public values, economic restructuring) and reduced organizational capacity, these demands represent a significant and complex challenge to public land management. One way of dealing with this situation is to use a framework to assist in working through this complexity. A framework, for the purpose of this report, is a process using...

Hubbell recently presented a theoretical framework, neutral models, for explaining large-scale patterns of community structure. This theory rests on the foundation of zero-sum ecological communities, that is, the assumption that the number of individuals in a community stays constant over time. If community abundances stay relatively constant, (i.e. approximating the zero-sum assumption) there is a key deductive prediction that on average across the entire community there should be strong negative covariance among species. We have used measures of community covariance to test for zero-sum...

The timber production and ecological effects of forest land development are influenced by both the rate and spatial distribution of forest land development, and how remaining undeveloped forest lands are managed. Regarding effects on management, research conducted in the U.S. South and in Oregon suggests that development can reduce the intensity with which landowners manage remaining forest lands, potentially reducing forest commodity production and influencing ecological conditions and processes. Prevailing hypotheses suggest that this process results on: (1) the gradual fragmentation of...

A recurrent theme in the development of U.S. forest policies has been the assertion of strong positive relations among communities, economies, and natural resource management. Now as a new round of federal land management planning is getting underway, questions are being raised about the strength of that assertion and how to view communities following a decade of reduced federal harvests. This report examines these questions considering the 433 communities in six Bureau of Land Management districts in western Oregon. It discusses the ways that forest-based communities have been considered...