Fuels & Fuel Treatments
This study evaluated the long-term (13 years post-treatment) effectiveness of prescribed fire and mechanical tree removal to re-establish sagebrush steppe vegetation and associated spatial patterns in ground surface conditions and soil hydrologic properties of two woodland-encroached sites. Specifically, we assessed the effects of tree removal on: (1) vegetation and ground cover at the hillslope scale (990 m2 plots) and (2) associated spatial patterns in point-scale ground surface conditions and soil hydrologic properties along transects extending from tree bases and into the intercanopy areas between trees. Both sites were in mid to late stages of woodland encroachment with extensive bare conditions (~60–80% bare ground) throughout a degraded intercanopy area (~75% of the domain) surrounding tree islands (~25% of domain, subcanopy areas). All treatments effectively removed mature tree cover and increased hillslope vegetation. Enhanced herbaceous cover (4–15-fold increases) in burned areas reduced bare interspace (bare area between plants) by at least 4-fold and improved intercanopy hydraulic conductivity (> than 2-fold) and overall ecohydrologic function. Mechanical treatments retained or increased sagebrush and generally increased the intercanopy herbaceous vegetation. Intercanopy ground surface conditions and soil hydrologic properties in mechanical treatments were generally similar to those in burned areas but were also statistically similar to the same measures in untreated areas in most cases. This suggests that vegetation and ground surface conditions in mechanical treatments are trending toward a significantly improved hydrologic function over time. Treatments had limited impact on soil hydrologic properties within subcanopy areas; however, burning did reduce the soil water repellency strength and the occurrence of strong soil water repellency underneath trees by three- to four-fold. Overall, the treatments over a 13-year period enhanced the vegetation, ground surface conditions, and soil hydrologic properties that promote infiltration and limit runoff generation for intercanopy areas representing ~75% of the area at the sites. However, ecological tradeoffs in treatment alternatives were evident. The variations in woodland responses across sites, treatments, and measurement scales in this long-term study illustrate the complexity in predicting vegetation and hydrologic responses to tree removal on woodland-encroached sagebrush sites and underpin the need and value of multi-scale long-term studies.
Description: The first webinar in a series of virtual learning opportunities that address the cultural shifts and adaptations that are being embraced at all levels to evolve and advance progress toward the vision and goals of the Cohesive Wildland Fire Strategy.
Presenter: Alan Ager, Research Forester, USFS Rocky Mountain Research Station
A brief look at how the Black Range of the Gila National Forest goes about putting down thousands of acres of prescribed fire. See how the District works in a collaborative and productive manner while working within the multiple-use framework to include grazing, wildlife, recreation, and community outreach. Supported by science, the agency looks to keep fire on the landscape.
Fire researchers discuss the return of fire to western U.S. landscapes in the context of wildfire history.
Hosted by Matt Reeves, using Microsoft Teams, click the “Watch on web instead” link to view.
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Frequent-fire forests of the western United States have undergone remarkable changes in structure, composition, and function due to historical exclusion of naturally occurring fire. Mechanized tree thinning to reduce forest density and fuel loads tends to be expensive and cannot be effectively implemented across all lands, and there is increasing interest in managing naturally ignited wildfires for meeting forest restoration objectives. To investigate general effectiveness of resource objective (RO) wildfires for restoring frequent-fire and associated forests of the western United States, a review of the related peer-reviewed literature was conducted.
Panel discussion on grazing for fire prevention with Tracy Schohr, UCCE Livestock and Natural Resources Advisor for Plumas, Sierra & Butte Counties.
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Exotic grasses are a widespread set of invasive species that are notable for their ability to significantly alter key aspects of ecosystem function. Understanding the role and importance of these invaders in forested landscapes has been limited but is now rising, as grasses from Eurasia and Africa continue to spread through ecosystems of the Americas, Australia, and many Pacific islands, where they threaten biodiversity and alter various aspects of the fire regime. The ecological, social and economic impacts of the grass-fire cycle associated with species such as cheatgrass (Bromus tectorum) have been long recognized in aridlands such as the iconic sagebrush ecosystems of the western US. However, the damaging impacts of invasive grasses in forestlands have received considerably less attention. We review literature, conceptual models, model output, and empirical evidence that indicate grass invasion in forest ecosystems may be an important yet largely under-recognized phenomenon. In combination with climate change, wildfire, and overstory management, invasive grasses could create a “perfect storm” that threatens forest resilience. Invasive grasses can be successful in forested environments or develop strongholds within forested mosaics and could provide the literal seeds for rapid change and vegetation type conversion catalyzed by wildfire or changes in climate. Although invasive grass populations may now be on the edge of forests or consist of relatively rare populations with limited spatial extent, these species may disrupt stabilizing feedbacks and disturbance regimes if a grass-fire cycle takes hold, forcing large portions of forests into alternative nonforested states. In addition, forest management actions such as thinning, prescribed fire, and fuel reduction may actually exacerbate invasive grass populations and increase the potential for further invasion, as well as broader landscape level changes through increased fire spread and frequency. Lack of understanding regarding the ecological consequences and importance of managing invasive grasses as a fuel may lead to unintended consequences and outcomes as we enter an age of novel and rapid ecological changes. This paper focuses on the contributory factors, mechanisms, and interactions that may set the stage for unexpected forest change and loss, in an effort to raise awareness about the potential damaging impact of grass invasion in forested ecosystems.
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Description: Webinar focuses on three critical areas of bioenergy and bioproducts research and development: 1) sustainable and economically efficient forest biomass management and production systems, 2) competitive low-emissions biofuels and bioenergy conversion technologies deployed in the forest sector, and 3) information and tools for decision making and policy analysis related to forest biomass utilization.
Presenter: Nate Anderson, PhD in Forest Resources Management from the State University of New York, an MS in Sustainable Development and Conservation Biology from the University of Maryland, and a BS in Biology from Bates College.