Treesearch

Old-growth coniferous forests of the Pacific Northwest are among the most productive temperate ecosystems and have the capacity to store large amounts of carbon for multiple centuries. To date, there are considerable gaps in modeling ecosystem fluxes and their responses to physiological constraints in these old-growth forests. These model shortcomings limit our ability to understand and project how the old-growth forests of the Pacific Northwest will respond to global climate change. This study applies the cohort-based Ecosystem Demography Model 2 (ED2) to the Wind River Experimental...

Wildland fire and ecological researchers use empirical and semi-empirical modeling systems to assess fire behavior and danger. This technical note describes the firebehavioR package, a porting of two fire behavior modeling systems, Crown Fire Initiation and Spread and a Rothermel-based framework, to the R programming language. We also highlight supporting data objects and functions to predict inputs required for fire behavior estimation. Last, this package contains functions for fifteen indices to express fire danger using weather and/or fuels observations. Specific advantages of predicting...

The Arctic is undergoing dramatic environmental change with rapidly rising surface temperatures, accelerating sea ice decline and changing snow regimes, all of which influence tundra plant phenology. Despite these changes, no globally consistent direction of trends in spring phenology has been reported across the Arctic. While spring has advanced at some sites, spring has delayed or not changed at other sites, highlighting substantial unexplained variation. Here, we test the relative importance of local temperatures, local snow melt date and regional spring drop in sea ice extent as...

This case study was developed as part of a larger, interdisciplinary research project to assess the social, hydrological, and ecological effects of beaver-related watershed restoration approaches in rangeland streams of the Western United States. It is one of five case studies being undertaken to investigate the social context of beaver- (Castor canadensis) related restoration in western rangelands. Research in the Bridge Creek watershed of the John Day River basin has found that beaver dam analogues (BDAs) improved habitat for fish listed under the Endangered Species Act, garnering...

Using an adaptation of Forest Inventory and Analysis’s BioSum framework, which models prospective management of forested landscapes using forest inventory data, we tested several fire-resistance-promoting restoration treatments, implemented with tethered cut-to-length harvest systems, for effectiveness and economic feasibility in the dry national forests of southern Oregon and northern California. Treatments elevated fire resistance on most forested area, primarily via increases in the separation of canopy and surface fuels and among tree crowns, and the most effective treatments could...

Forests represent a significant opportunity for carbon sequestration, but quantifying biomass change at the landscape scale and larger remains a challenge. Here we develop an approach based on repeated tree-level analysis using high-resolution airborne lidar (around 8 pulses/m2). The study area was 53 km2 of actively managed coniferous forestland in the Coast Range Mountains in western Oregon. The study interval was 2006–2012. Tree heights and crown areas were determined from the lidar data using point cloud clustering. Biomass per tree was estimated with allometry. Tree-level data (N =...

In an Area Based Approach (ABA) to forest inventories using Airborne Laser Scanning (ALS) data, the sample plot size may vary or the cell size may differ from the plot size. Although this resolution mismatch may cause bias and increase in prediction error, it has not been thoroughly studied. The aim of this study was to clarify the meaning of resolution dependence in ABA, and to further identify its causal factors and quantify their effects. In general, a number of factors contribute to resolution dependence in ABA forest inventories, including the varying point density of the ALS data,...

The commercial use of low-value forest-origin biomass has long been considered for its potential to offset the cost of reducing wildfire hazard. The production of biochar simultaneously consumes low-value forest biomass and produces stable charcoal that, when applied to dryland agricultural soils, can increase water holding capacity and crop yield. In this way the production of forest-origin biochar has the potential to promote forest restoration, foster forest-related employment, increase agricultural competitiveness, and sequester carbon. Biochar offers the greatest opportunity where...

Aims: Plant responses to disturbances and environmental variation can manifest in communities as compositional nestedness (i.e., one community is a subset of another) and/or turnover (two communities represent different compositional gradient spaces). Yet, different sampling designs can artificially give an illusion of such compositional differences among two datasets, making it problematic to harmonize them in multi-species analysis. We test the prediction that sampling differences which increase beta- diversity components (nestedness and turnover) among two vegetation datasets will...

There is growing concern that populations of fire-adapted species around the world are at risk of extirpation due to 20th century fire exclusion (i.e. senescence risk). Concurrently, increasing fire activity in many regions is prompting concern that repeated, short-interval fire poses a risk to young stands before trees reach reproductive maturity (i.e. immaturity risk). Conceptual models assessing vulnerability to both risks exist, yet there is a lack of empirically-based studies that assess the effects of anthropogenically-altered fire regimes across the entire range of a fire-adapted...