Treesearch

Wound closure is an important component of tree recovery from bole damage. Damage to young Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stands in the precommercial and commercial stages is common, yet few studies have looked at how trees at these stages of stand development respond to common forms of damage. Using data from a 10-year study of artificially damaged Douglas-fir trees, we found reduced potential for relative wound closure with increasing initial tree bole diameter, and increasing initial relative bole area damaged. Wound-closure rates increased for longer periods of time...

Fire plays an important role in wildland ecosystems, critical to sustaining biodiversity, wildlife habitat and ecosystem health. By area, 70% of US prescribed burns take place in the Southeast, where treatment objectives range widely and accomplishing them depends on finding specific weather conditions for the effective and controlled application of fire. The climatological variation of the preferred weather window is examined here using two weather model reanalyses, with focus on conditions critical to smoke dispersion and erratic fire behaviour. Large spatial gradients were evident in...

The Blue Mountains Adaptation Partnership (BMAP) was established to increase climate change awareness, assess vulnerability to climate change, and develop science-based adaptation strategies for national forest lands in the Blue Mountains region of northeast Oregon and southeast Washington (USA). The BMAP process included (1) development of a science-management partnership, (2) a vulnerability assessment of the effects of climate change on natural resources and infrastructure, (3) development of adaptation options that will help reduce negative effects of climate change and assist the...

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...