Treesearch

We developed ecologically based climate‐fire projections for the western United States. Using a finer ecological classification and fire‐relevant climate predictors, we created statistical models linking climate and wildfire area burned for ecosections, which are geographic delineations based on biophysical variables. The results indicate a gradient from purely fuel‐limited (antecedent positive water balance anomalies or negative energy balance anomalies) to purely flammability‐limited (negative water balance anomalies or positive energy balance anomalies) fire regimes across ecosections....

The Haines Index is intended to provide information on how midtropospheric conditions could lead to large or erratic wildfires. Only a few studies have evaluated its performance and those are primarily single fire studies. This study looks at 47 fires that burned in the United States from 2004 to 2017, with sizes from 9000 ha up to 218,000 ha based on daily fire management reports. Using the 0-h analysis of the North American Model (NAM) 12 km grid, it examines the performance of the start-day Haines Index, as Haines (1988) originally discussed. It then examines performance of daily Haines...

Many fire-maintained savannas and woodlands are suffering the effects offire exclusion and the concomitant invasion of fire-sensitive trees. In the Pacific West, woodlands dominated by either Oregon white oak (Quercus garryana) or California black oak (Quercus kelloggii) have transitioned from oak-dominated to conifer-dominated (primarily by the native Douglas-fir; Pseudotsuga menziesii) forest conditions with corresponding losses of plant and animal biodiversity. In spite of the prevalence of this transition, few studies have documented these temporal shifts and the consequences for oak...

Fuel-reduction treatments have been used effectively in dry, fire-adapted forests to reduce risk of high-severity crown fire, but it is less certain whether they achieve ecological objectives such as promoting understory diversity. Using long-term data from a fuel-reduction experiment, we tested how conclusions about treatment effectiveness are related to the spatial and temporal scales over which ecological responses are evaluated. We modeled the richness of herbs and shrubs at smaller (1–50m2) and larger (1000m2) spatial scales as functions of pre-treatment richness, thinning intensity,...

The Hungry Bob fuels reduction project was part of a 12-site National Fire and Fire Surrogate (FFS) network of experiments conducted across the United States from the late 1990s through the early 2000s to determine the regional differences in applying alternative fuel-reduction treatments to forests. The Hungry Bob project focused on restoration treatments applied in low elevation, dry second-growth ponderosa pine (Pinus ponderosa subsp. ponderosa (Douglas ex C. Lawson) and Douglas-fir (Pseudotsuga menziesii subsp. glauca (Beissn.) Franco forests of northeastern Oregon. Treatments included...

Regeneration performance of planted grand fir (Abies grandis [Dougl. ex D. Don] Lindl.), coast Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii), western redcedar (Thuja plicata Donn ex D. Don), and western hemlock (Tsuga heterophylla [Raf.] Sarg.) seedlings was studied for 3 years within artificial canopy gaps in a mature Douglas-fir forest near Tacoma, WA. Third-year survival of Douglas-fir and western redcedar did not vary with gap size, but peak survival of grand fir and western hemlock occurred at gap sizes of 0.13 and 0.14 ha (0.32 and 0.35 ac), respectively. Peak...

To examine the effects of taproot deformity on stem curvature, 90 full-sibling loblolly pine (Pinus taeda L.) seedlings (30 seedlings each from 3 families) were planted with 5 root/stem form treatments: straight taproot (control treatment), straight taproot with underground obstruction, taproot planted with J-root form, taproot planted at a 45-degree angle, and a straight taproot with the stem pulled to a 45-degree angle. Significant treatment differences (P ≤ 0.05) were found in year 1 for stem diameter and frequency of interwhorl oscillations, and all variables differed significantly...

Declines in populations of Pacific salmon have prompted extensive and costly restoration efforts, yet many populations are still in peril. An improved understanding of landscape-scale controls on salmon habitat should help focus restoration resources on areas with the greatest potential to host productive habitat. We investigate the contribution of deep-seated landslides (DSLs) to Coho Salmon habitat by comparing the quantity and connectivity of potential seasonal habitat observed in five streams with extensive DSLs to five lacking significant landsliding. Further, we measure valley width...

Pools provided by beaver (Castor canadensis) contribute to critical habitat requirements of salmonids in fluvial systems of the Pacific Northwest, therefore more land managers are interested in managing watersheds that include beavers or engaging in beaver-related restoration projects. We evaluated the utility of applying an existing beaver habitat suitability model to better understand beaver dam site characteristics in coastal Oregon, identify optimum dam site locations, and guide future beaver-related restoration efforts. We used a combination of t-tests, Wilcoxon rank sum tests, and a...

Prescribed fire is an active management tool used to address wildfire hazard and ecological concerns associated with fire exclusion and suppression over the past century. Despite widespread application in the United States, there is considerable inconsistency and lack of information regarding the extent to which specific outcomes are achieved and under what prescribed fire regimes, particularly in regard to ecological goals related to plant community structure. We quantify differences and patterns in plant functional group abundance, species richness and diversity, and other key forest...