Treesearch

Thermocouples were used to measure gas temperatures as a function of distance to the edge of a rectangular burner. Experiments varied the energy release rate, burner aspect ratio, wind speed, and surface inclination angles. Mean gas temperature was nearly constant over the distance that flames attached to the down-wind or uphill surface. Beyond this region, mean temperature profiles declined as a power-function of distance, primarily due to increasing intermittency of flame impingement. A linear regression model characterized the power-law temperature profile and flame intermittency. The...

We present a new R package to provide dendroecologists with tools to infer, quantify, analyze, and visualize growth suppression events in tree rings. dfoliatR is based on the OUTBREAK program and builds on existing resources in the R computing environment and the well-used dplR package. It is designed to aid research in the ecology of insect defoliation events and to reconstruct defoliator outbreak chronologies, but can be applied to other studies where host-non-host comparisons are useful. dfoliatR performs an indexing procedure to remove climatic signals in the host-tree series that are...

Populations of cold-adapted species at the trailing edges of geographic ranges are particularly vulnerable to the negative effects of climate change from the combination of exposure to warm temperatures and high sensitivity to heat. Many of these species are predicted to decline under future climate scenarios, but they could persist if they can adapt to warming climates either physiologically or behaviourally. We aim to understand local variation in contemporary habitat use and use this information to identify signs of adaptive capacity. We focus on moose (Alces alces), a charismatic...

Warmer climatic conditions have been associated with numerous hydrologic changes that may impact riverbank erosion in cold regions, but the net effect is not well understood. We used regression and correlation analyses to examine the relationships among subarctic riverbank erosion and seasonal hydrology, the impact of climate change and variability, and the societal implications. Geomorphic change (loss and gain of vegetated land) was mapped along several river reaches in the Yukon River Basin, Alaska, throughout 1984 and 2017 using Landsat satellite imagery. Annual erosion rates were...

Annual tree-ring patterns are a source of ecological and environmental information including the history of fires in forested areas. Tree-ring based fire histories include three fundamental phases: field collection, laboratory methods (preparation and dating), and data analysis. Here we provide step-by-step instructions and issues to consider, including the process for selecting the study area, sampling sites, plus how and which fire-scarred trees to sample. In addition, we describe fire-scar sample preparation and dating which are done in the laboratory. Finally, we describe basic...

Accurate and complete geospatial fire occurrence records are important in determining postfire effects, emissions, hazards, and fuel loading inventories. Currently, the Monitoring Trends in Burn Severity (MTBS) project maps the fire perimeter and burn severity of all large fires on public lands. Although the MTBS project maps a large proportion of the fire acreage, it maps a smaller proportion of the actual number of fires in the United States, thereby creating a data gap. To fill this data gap, fire scientists at the U.S. Geological Survey (USGS) Earth Resources Observation and Science...

Wildfire risk assessments rely on flame-length probabilities - the conditional probabilities that fire intensity will be within various flame-length classes. The factors affecting flame-length probability include the elements of the fire-behavior triangle - fuel, weather, and topography - plus the orientation of the flaming front relative to the heading direction. Current methods for determining flame-length probabilities include: (1) a single deterministic simulation of flame length at the head of the fire for one weather type (wind speed, wind direction, fuel moisture content); (2)...

Rehabilitation Capability Convergence for Ecosystem Recovery (RECOVER) postfire decision support system is a server-based application designed to rapidly provide land managers with the information needed to develop a comprehensive rehabilitation plan. This study evaluated the efficacy of RECOVER through structured interviews with land managers (n = 20) who used RECOVER and were responsible for postfire rehabilitation efforts on over 715,000 ha of fire-affected lands. Although the benefit of better-informed decisions is difficult to quantify, the results of this study illustrate that...

The Terai Arc Landscape (TAL) is an ecologically important region of the Indian subcontinent, where anthropogenic habitat loss and forest fragmentation are major issues. The most prominent threat is forest fires because of their impacts on the microhabitat and macrohabitat characteristics and the resulting disruption of ecological processes. Moreover, wildfire aggravates conflicts between humans and wildlife in the forest fringe areas. The lack of a proper forest fire monitoring system in the TAL is a major management issue that needs attention for long-term forest viability. Hence, the...

Spatial wildfire risk assessments that account for both the probability and consequences of wildfire events are becoming an important element of strategic wildland fire and fuels planning (Calkin et al. 2011; Finney 2005; Gilbertson-Day et al. 2017, 2018; Thompson et al. 2013, 2016a). Using a standardized framework (Scott et al. 2013), these assessments can be scaled from local communities up to the continental scale. Inputs, spatial resolution, and methodology considerations change with different assessment scales, as do the types of questions that can be addressed with the results. The...