Treesearch

Until recently, scientific understanding of the history and ecology of the Pacific Northwest's mixed-conifer forests east of the Cascade Range was minimal. As a result, forest managers have had limited ability to restore the health of publicly owned forests that show signs of acute stress caused by insects, disease, grazing, logging, and wildfire. A recent study co-authored by a Pacific Northwest Research Station research forester revealed that the traditionally used term "mixed-conifer forest" is too broad for ecological management. The study fills a knowledge gap by providing evidence...

Forest ecosystems play a critical role in mitigating greenhouse gas emissions. Forest carbon (C) is stored through photosynthesis and released via decomposition and combustion. Relative to C fixation in biomass, much less is known about C depletion through decomposition of woody debris, particularly under a changing climate. It is assumed that the increased temperatures and longer growing seasons associated with projected climate change will increase the decomposition rates (i.e., more rapid C cycling) of downed woody debris (DWD); however, the magnitude of this increase has not been...

Carbon stored in harvested wood products is recognized under international carbon accounting protocols, and some crediting systems may permit the inclusion of harvested wood products when calculating carbon sequestration. For managers and landowners, however, estimating carbon stored in harvested wood products may be difficult. PRESTO (PRoduct EStimation Tool Online) is a Web-based tool that enables users to easily estimate the carbon stored in harvested wood products and the changes in this quantity over time. The tool may be used in an exploratory mode to examine the impacts of changing...

Eastern hemlock, Tsuga Canadensis (L.) Carriere, and Carolina hemlock, Tsuga caroliniana Engelmann, provide unique habitat that is threatended by the invasive hemlock woolly adelgid, Adelges tsugae Annand, which arrived in Georgia in 2003. In an attempt to conserve a portion of the mature hemlocks in north Georgia, the USDA Forest Service created over 100 Hemlock Conservation Areas throughout the Chattahoochee National Forest and designated them to receive chemical and/or biological control.

Hemlock woolly adelgid, Adelges tsugae Annand, is currently found throughout most of the range of eastern hemlock, Tsuga Canadensis (L.) Carriere. Biological control agents have been released in attempts to control this pest, but how different climates influence the efficacy and survival of these agents has not been studied.

Land management planning at broad scales requires integrative techniques to understand and synthesize the effects of different land management activities and address socioeconomic and conservation concerns. The Integrated Landscape Assessment Project was developed to support the vital but complex task of broadscale integration of information to assess ecological sustainability at multiple scales. The project supports ecosystem management planning at a regional scale across all lands of Arizona, New Mexico, Oregon, and Washington by simulating landscape dynamics using state-and-transition...

Information on the effects of management activities such as fuel reduction treatments and of processes such as vegetation growth and disturbance on fire hazard can help land managers prioritize treatments across a landscape to best meet management goals. State-and-transition models (STMs) allow landscape-scale simulations that incorporate effects of succession, management, and disturbance on vegetation composition and structure. State-and-transition models have been used for many different types of landscape-scale assessments. However, STMs do not currently assess fuels and fire hazard for...

The sensitivity of soil organic carbon (SOC) to changing environmental conditions represents a critical uncertainty in coupled carbon cycle–climate models1.Much of this uncertainty arises from our limited understanding of the extent to which root–microbe interactions induce SOC losses (through accelerated decomposition or ‘priming’2) or indirectly promote SOC gains (via ‘protection’ through interactions with mineral particles3,4). We developed a new SOC model to examine priming and protection responses to rising atmospheric CO2. The model captured disparate SOC responses at two temperate...

The analysis of phylogenetic relationships among co-occurring tree species offers insights into the ecological organization of forest communities from an evolutionary perspective and, when employed regionally across thousands of plots, can assist in forest health assessment. Phylogenetic clustering of species, when species are more closely related than expected by chance, suggests a process of evolutionary niche conservatism. Because such communities share much evolutionary history and an affinity for similar environmental conditions, they may be particularly susceptible to threats such as...

Forest land provides various ecosystem services, including timber, biomass, and carbon sequestration. Estimating trends in these ecosystem services is essential for assessing potential outcomes of landscape management scenarios. However, the state-and transition models used in the Integrated Landscape Assessment Project for simulating landscape changes over time do not directly compute the variables necessary for volume and biomass estimation. This study illustrates a methodology for modeling timber production and biomass supply potential over time in central Washington, and gives an...