Treesearch

Debris avalanches occasionally occur with the partial collapse of a volcano, and their ecological impacts have been studied worldwide. Examples include Mt. Taranaki in New Zealand (Clarkson 1990), Ksudach in Russia (Grishin et al. 19961, the Ontake volcano in Japan (Nakashizuka et al. 1993), and Mount Katmai in the state of Alaska in the United States (Griggs 1918a,b, 1919). Analyses have shown that as many as 18 previously undetected debris avalanches have flowed from the Hawaiian island volcanoes (Moore and Clague 1992). Following the debris avalanche at Mount Katmai in Alaska, Griggs...

Research and operational trials have identified methods of forest plantation establishment that promote high rates of survival and early growth of tree seedlings in the Pacific Northwest. Primary reasons for this success are the intensive control of competing vegetation provided by herbicide treatments and the planting of high quality seedlings. This paper discusses the current state of the art in forest plantation establishment in Oregon and Washington west of the crest of the Cascade Range. It considers technologies developed in the last two decades that currently have widespread...

In the past decade, LIDAR (light detection and ranging) has emerged as a powerful tool for remotely sensing forest canopy and stand structure, including the estimation of aboveground biomass and carbon storage. Numerous papers have documented the use of LIDAR measurements to predict important aspects of forest stand structure, including aboveground biomass. Other papers have documented the ability to transform LIDAR measurements to approximate common field measures, such as cover, stand height, and vertical distributions of foliage density and light transmittance. However, only a small...

We investigated the effect of fire severity and environmental conditions on conifer tree regeneration 11 years after an autumn wildfire in the western Oregon Cascade Range. Conifer tree seedlings, including those of Pseudotsuga menziesii, established promptly and at high densities following fire, in contrast to long establishment periods documented for many other sites. P. menziesii, Tsuga heterophylla and Thuja plicata comprised 99.0% of the seedlings measured in the study. Pseudotsuga seedling density was greater on sites that had burned with moderate and high severity compared to low...

There is a need to identify measurable characteristics of stream channel morphology that vary predictably throughout stream networks and that influence patterns of hyporheic exchange flow in mountain streams. In this paper we characterize stream longitudinal profiles according to channel unit spacing and the concavity of the water surface profile. We demonstrate that: (1) the spacing between zones of upwelling and downwelling in the beds of mountain streams is closely related to channel unit spacing; (2) the magnitude of the vertical hydraulic gradients (VHGs) driving hyporheic exchange...

This report presents results from monitoring spotted owl (Strix occidentalis caurina) populations and habitat during the first 10 years of implementation of the Northwest Forest Plan (the Plan). Estimated population decline ranged from 0 to 10 percent across study areas (weighted average of 3.4 percent) annually. The average annual rate of decline for the four demographic areas in Washington was 7.1 percent. Presence of barred owls (Strix varia), weather, past and present harvest of habitat, and wildfire and insect infestations that alter habitat are all possible contributors to the noted...

Although the Northwest currently has the least proportion of non-native invasive plant species relative to other regions or North America, invasions continue to increase into the mountainous areas of the region. Landscape structure, such as the variation found along the complex gradients of the Northwest mountain ecoregions, affects the expansion of invasive plant species and the invasibility of plant communities. Also, the history of land use and current use patterns affect the expansion of invasive plants, and many of the deteriorated environments in the region's mountains may invite and...

Airborne laser scanning of forests has been shown to provide accurate terrain models and, at the same time, estimates of multiple resource inventory variables through active sensing of three-dimensional (3D) forest vegetation. Brief overviews of airborne laser scanning technology [often referred to as "light detection and ranging" (LIDAR)] and research findings on its use in forest measurement and monitoring are presented. Currently, many airborne laser scanning missions are flown with specifications designed for terrain mapping, often resulting in data sets that do not contain key...

Airborne laser scanning is a technology developed in the last 15 years. Commonly referred to as light detection and ranging, or LIDAR, these systems can map ground with up to a 6-inch elevation accuracy in open, flat terrain. LIDAR is being rapidly adopted for topographical and flood-plain mapping and the detection of earthquake faults hidden by vegetation, among other uses. Most analysis begins with a process known as "bare-earth filtering"—laser scan data about trees and buildings are stripped away to leave just the bare-ground data. These discarded data, however, are extremely valuable...

Utilization of small diameter trees is viewed by many as the key to making landscape-scale fuel treatment financially feasible. But little capacity currently exists for utilizing such material and capacity of sufficient scale to have a significant impact on the economics of small diameter removals will only be added if predictable feedstocks can be assured. The FIA BioSum modeling framework that incorporates Forest Inventory and Analysis (FIA) plot data, a transportation cost model, a treatment cost accounting module, a log valuation model, and a crown fire hazard evaluator was applied to...