Treesearch

Since 1973, the National Silviculture Workshop has provided a forum for USDA Forest Service managers and scientists to deliberate on management topics, issues, or challenges that reflect the progression of Federal forest management in the United States (Table 1). Rotating the meeting location around the United States to expose the attendees to many different ecosystems and management concerns and practices, early workshops explored techniques of uneven-aged management, controlling stand density in second-growth stands, tree improvement, and fertilization for timber management (Barton et...

Following high-severity wildfire, application of mulch on the soil surface is commonly used to stabilize slopes and limit soil erosion potential, protecting ecosystem values at risk. Despite the widespread use of mulch, relatively little is known about its effects on ecosystem recovery and soil processes important for plant re-establishment. Following a high-severity wildfire in a Colorado lodgepole pine forest, we studied the effects of both mulch material and application rate on plant recovery and the relative importance of soil abiotic conditions and microbial substrate availability as...

Pyrenophoric acid (P-Acid), P-Acid B, and P-Acid C are three phytotoxic sesquiterpenoids produced by the ascomycete seed pathogen Pyrenophora semeniperda, a fungus proposed as a mycoherbicide for biocontrol of cheatgrass, an extremely invasive weed. When tested in cheatgrass bioassays, these metabolites were able to delay seed germination, with P-Acid B being the most active compound. Here, we have investigated the cross-kingdom activity of P-Acid B and its mode of action, and found that it activates the abscisic acid (ABA) signaling pathway in order to inhibit seedling establishment....

Seasonal snow is an important component of Earth's hydrologic cycle and climate system, yet it remains challenging to consistently and accurately measure snow depth and snow water equivalent (SWE) across the range of diverse snowpack conditions that exist on Earth. The NASA SnowEx campaign is focused on addressing the primary gaps in snow remote sensing in order to gain an improved spatiotemporal understanding of this important resource and to further efforts toward a future satellite-based snow remote sensing mission. Ground‐penetrating radar (GPR) is an efficient and mature approach for...

Background: Forest management, especially restoration, is informed by understanding the dominant natural disturbance regime. In many western North American forests, the keystone disturbance is fire, and a plethora of research exists characterizing various fire regime parameters, although often only one or two parameters are addressed in individual studies. I performed a systematic review of the literature and meta-analysis of the derived data from 26 publications to characterize five parameters of the historical fire regime of ponderosa pine (Pinus ponderosa Lawson & C. Lawson) ecosystems...

Coordinated approaches to wildfire risk mitigation strategies that cross-ownership and management boundaries are found in many policies and programs worldwide. The “all lands” approach of the United States (US) National Cohesive Strategy, for example, attempts to address the mismatches between biophysical risk and the social potential to address risks by improving multijurisdictional coordination and collaboration. Local capacity to coordinate wildfire risk mitigation, therefore, may be an important influence on whether risk reduction planning makes success stories out of at-risk communitie...

Pine wilt disease is one of the most serious introduced threats to coniferous forests worldwide. Its causal agent, the pinewood nematode (PWN), Bursaphelenchus xylophilus, is vectored primarily by cerambycids of the genus Monochamus Dejean throughout its native (North America) and introduced (Japan, China, Korea, Taiwan, Portugal) ranges. Despite strict import regulations and phytosanitary measures, interception records indicate that PWN and Monochamus species continue to be moved worldwide. Following its introduction in Portugal in the late 1990s, extensive monitoring programs for PWN and...

The relationship between wildland fire spread rate and wind has been a topic of study for over a century, but few laboratory studies report measurements in controlled winds exceeding 5 m s−1. In this study, measurements of fire rate of spread, flame residence time and energy release are reported for fires burning under controlled atmospheric conditions in shallow beds of pine needles subject to winds ranging from 0 to 27 m s−1 (measured 5 m above ground level). The data suggested that under constant flow conditions when winds are less than 10 m s−1, fire rate of spread increases linearly...

Concerns over wildfire impacts to water supplies have motivated efforts to mitigate risk by reducing forest fuels. Methods to assess fuel treatment effects and prioritise their placement are needed to guide risk mitigation efforts.We present a fuel treatment optimisation model to minimise risk to multiple water supplies based on constraints for treatment feasibility and cost. Risk is quantified as the expected sediment impact costs to water supplies by combining measures of fire likelihood and behaviour, erosion, sediment transport and water supply vulnerability. We demonstrate the model’s...

The high biodiversity of the Mexican montane forests is concentrated on the Trans-Mexican Volcanic Belt, where several Protected Natural Areas exist. Our study examines the projected changes in suitable climatic habitat for five conifer species that dominate these forests. The species are distributed sequentially in overlapping altitudinal bands: Pinus hartwegii at the upper timberline, followed by Abies religiosa, the overwintering host of the Monarch butterfly at the Monarch Butterfly Biosphere Reserve, P. pseudostrobus, the most important in economic terms, and P. devoniana and P....