Treesearch

Shrubs are an important component of terrestrial plant communities in both forested and nonforested ecosystems, but relatively little information is available on their distributions. This project provides mapped occurrences for 78 native shrub species found in the Pacific Northwest (Oregon, Washington, Idaho, and western Montana) as derived from two large regional databases: the U.S. Department of Agriculture, Forest Service Forest Inventory and Analysis database of vegetation collected as part of a nationwide forest inventory and the Consortium of Pacific Northwest Herbaria online...

A growing body of research shows that plant genetic factors can influence ecosystem processes and structure communities, but one aspect that has received little study is sex differentiation in dioecious plants. Since headwater streams are reliant on riparian leaf litterfall, plant sex differences in leaf traits may influence in-stream processes. Sitka willow (Salix sitchensis) at Mount St. Helens is dioecious and heavily infested with the stem-boring weevil (Cryptorhynchus lapathi), which causes branch dieback and summer litterfall. We found that female willow shrubs tend to grow closer to...

Background: Recent increases in forest tree mortality should increase the abundance coarse woody detritus (CWD) and ultimately lead to increased atmospheric carbon dioxide. However, the time course of carbon release from CWD is not well understood. We compiled CWD decomposition rate-constants (i.e., k) to examine how tree species, piece diameter, position (i.e., standing versus downed), canopy openness, and macroclimate influenced k. To illustrate their implications we modeled the effect of species and position on estimates of decomposition-related carbon flux. We examined a subset of...

The Demonstration of Ecosystem Management Options (DEMO) Study is an operational-scale experiment in variable-retention harvests with six installations in western Washington and Oregon. Initiated in 1994, the experiment was designed to test key assumptions underlying standards and guidelines in the Northwest Forest Plan for regeneration harvests on matrix lands. The orthogonal portion of the six-treatment design (15 and 40 percent retention in both aggregated and dispersed patterns) is unique among large-scale variable-retention experiments, allowing for independent tests of responses to...

Resource managers are under increasing pressure to prioritize conservation efforts by assessing climate risk for numerous species. Amphibians, fish, and reptiles are particularly vulnerable to habitat alteration and climate change, yet many species fly under the conservation radar due to lack of basic information.Dede Olson, a research ecologist with the Pacific Northwest Research Station, has forged science partnerships among researchers from diverse disciplines that are yielding rapid advances in species threat assessments.Olson and three U.S. Geological Survey scientists developed an...

Novel outbreaks of emerging pathogens require rapid responses to enable successful mitigation. We simulated a 1-day emergency meeting where experts were engaged to recommend mitigation strategies for a new outbreak of the amphibian fungal pathogen Batrachochytrium salamandrivorans. Despite the inevitable uncertainty, experts suggested and discussed several possible strategies. However, their recommendations were undermined by imperfect initial definitions of the objectives and scope of management. This problem is likely to arise in most real-world emergency situations. The exercise thus...

Insects and pathogens are widely recognized as contributing to increased tree vulnerability to the projected future increasing frequency of hot and dry conditions, but the role of parasitic plants is poorly understood even though they are common throughout temperate coniferous forests in the western United States. We investigated the influence of western hemlock dwarf mistletoe (Arceuthobium tsugense) on large (≥45.7 cm diameter) western hemlock (Tsuga heterophylla) growth and mortality in a 500 year old coniferous forest at the Wind River Experimental Forest, Washington State, United...

We contribute to addressing two gaps that reduce the utility of ecosystem sciences for decision-making: lack of standard methods for using stakeholders’ knowledge to co-design ecosystem services science research, and absence of commensurable social valuation metrics that allow effective value comparisons. In two phases, we used co-designed instruments to conduct social valuation of biodiversity, and provisioning, cultural and regulating services. First, we conducted eight participatory fora, where experts and non-experts identified ecosystem aspects to which they ascribe value. We combined...

Diameter distributions and tree-lists provide information about forest stocks disaggregated by size and species and are key for informing forest management. Diameter distributions and tree-lists are multivariate responses, which makes the evaluation of methods for their prediction reliant on the use of dissimilarity metrics to summarize differences between observations and predictions. We compared four strategies for selection of k nearest neighbors (k-NN) methods to predict diameter distributions and tree-lists using LiDAR and stand-level auxiliary data and analyzed the effect of the k-NN...

The Forest Inventory and Analysis (FIA) program reports on the status and trends of Washington’s forest resources, producing comprehensive updates every 5 years. This report provides detailed estimates of forest area, tree species composition and distribution, volume, biomass, carbon, standing dead trees and down wood, and understory vegetation on forest land for the state of Washington. It also includes estimates of annual growth, mortality, and removals on forest land. Estimates are based on inventory data collected on 6,112 forested FIA plots in Washington between 2007 and 2016. There...