Synthesis / Tech Report
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The primary objective of this study was to explore the application of a dynamic global vegetation model (DGVM), the Ecosystem Demography (EDv2.2), to understand vegetation dynamics and ecosystem productivity in varying climate and fire scenarios. Most vegetation models do not represent sagebrush’s physical and physiological functions. Thus, we developed a sagebrush plant functional type (PFT) to use in modeling. Associated with this, the researchers performed a series of analyses and evaluations of the sagebrush and in the context of scenarios under natural (undisturbed) and disturbed (fire) environments.
- Results indicate that a number of sagebrush parameters are most sensitive to how productive the plant is (in our model). These include specific leaf area (SLA), stomatal slope, fine root turnover rate, cuticular conductance, and maximum carboxylation rate. These findings allow future sagebrush modeling efforts to further refine these parameters in different environments.
- The researchers comparisons between model runs and field data from Reynold Creek Experimental Watershed (RCEW), show good agreement. Improvements are needed to refine the model with additional PFTs representative of a range of elevations in the Great Basin.
- The researchers fire scenario modeling suggested that fire substantially reduced shrub gross primary production (GPP) and it took several decades before it was restored to pre-fire conditions. Grass GPP, however, responded more quickly in post-fire conditions. While these processes are representative of field observations and other studies, additional PFTs and improvement in fire routines in the model will provide for a better prognosis of future ecosystem dynamics of the sagebrush-steppe.
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View the complete pinyon-juniper synthesis
View fact sheet on pinyon-juniper ecology
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View fact sheet on pinyon-juniper ecohydrology
View fact sheet on pinyon-juniper management and restoration
This synthesis reviews current knowledge of pinyon and juniper ecosystems, in both persistent and newly expanded woodlands, for managers, researchers, and the interested public. We draw from a large volume of research papers to centralize information on these semiarid woodlands. The first section includes a general description of both the Great Basin and northern Colorado Plateau. The ecology section covers woodland and species life histories, biology, and ecology and includes a detailed discussion of climate and the potential consequences of climate change specific to the Great Basin and Colorado Plateau. The history section discusses 20,000 years of woodland dynamics and geographic differences among woodland disturbance regimes and resilience. The ecohydrology section discusses hydrologic processes in woodlands that influence soil conservation and loss; water capture, storage, and release; and the effect that woodland structure and composition have on these processes. The final section, restoration and management, covers the history of woodland management, the different methods used, the advantages and disadvantages of different vegetation treatments, and posttreatment vegetation responses. We also discuss successes and failures and key components that determine project outcomes important for consideration when restoring ecosystem function, integrity, and resilience.
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This report is part of an ongoing process of annual monitoring. It describes current conditions but is not an analysis or a description of a change of conditions. Although annual reports were produced for the years 2016 and 2017, the 2019 report also includes information from 2018. The 2019 report shows that:
- FS projects improved habitat for sage-grouse on nearly 480,000 acres from 2016-2019.
- Fires burned approximately 260,000 acres of greater sage-grouse habitat on National Forest System lands in 2016-2019.
- Data on habitat degradation are available from 2015-2018, and cumulative anthropogenic disturbance was at 0.03% on greater sage-grouse biologically significant units.
- Greater sage-grouse numbers in western states continue to cycle and are currently within the natural range of variability.
Keys to greater sage-grouse management are maintenance of expansive stands of sagebrush, especially varieties of big sagebrush with abundant forbs in the understory, particularly during spring; undisturbed and somewhat open sites for leks; and healthy perennial grass and forb stands intermixed with sagebrush for brood rearing. Within suitable habitats, areas should have 15–25% canopy cover of sagebrush 30–80 cm tall for nesting and 10–25% canopy cover 40–80 cm tall for brood rearing. In winter habitats, shrubs should be exposed 25–35 cm above snow and have 10–30% canopy cover exposed above snow. In nesting and brood-rearing habitats, the understory should have at least 15 percent cover of grasses and at least 10 percent cover of forbs greater than or equal to 18 cm tall. Greater sage-grouse have been reported to use habitats with 5–110 cm average vegetation height, 5–160 cm visual obstruction reading, 3–51% grass cover, 3–20% forb cover, 3–69 percent shrub cover, 7–63% sagebrush cover, 14–51% bare ground, and 0–18% litter cover. Unless otherwise noted, this account refers to habitat requirements and environmental factors affecting greater sage-grouse but not Gunnison sage-grouse. Habitats used by Gunnison sage-grouse are generally similar to habitats used by Greater Sage-Grouse, but some differences have been reported. The greater sage-grouse is a game bird and is hunted throughout most of its current range. This account does not address harvest or its effects on populations; rather, this account focuses on the effects of habitat management.
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Managers can use the First Order Fire Effects Model (FOFEM) when planning prescribed burns to achieve mortality-related objectives and for creating post-fire salvage guidelines to predict which trees will die soon after fire. Of the preceding observations, 13,460 involved trees that burned twice. Researchers evaluated the post-fire tree mortality models in FOFEM for 45 species. Approximately 75% of models tested in the FOFEM had either excellent or good predictive ability. Models performed best for thick-barked conifer species. Models tend to overpredict mortality for conifers with moderate bark thickness and underpredict mortality in primarily angiosperms or thin-barked conifers. Managers who rely on these models can use the results to (1) be aware of the uncertainty and biases in model predictions and (2) choose a threshold for assigning dead and live trees that optimizes certainty in either identifying or predicting live or dead individuals.
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The South-Central Oregon Adaptation Partnership (SCOAP) was developed to identify climate change issues relevant for resource management on federal lands in south-central Oregon. This science-management partnership assessed the vulnerability of natural resources to climate change and developed adaptation options that minimize negative impacts of climate change and facilitate transition of diverse ecosystems to a warmer climate. The vulnerability assessment shows that the effects of climate change on hydrology in south-central Oregon will be highly significant. Decreased snowpack and earlier snowmelt will shift the timing and magnitude of streamflow; peak flows will be higher, and summer low flows will be lower. Projected changes in climate and hydrology will have far-reaching effects on aquatic and terrestrial ecosystems, especially as frequency of extreme climate events (drought, low snowpack) and ecological disturbances (flooding, wildfire, insect outbreaks) increase.
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Wildland fires in the contiguous United States (CONUS) have increased in size and severity, but much remains unclear about the impact of fire size and burn severity on water supplies used for drinking, irrigation, industry, and hydropower. While some have investigated large-scale fire patterns, long-term effects on runoff, and the simultaneous effect of fire and climate trends on surface water yield, no studies account for all these factors and their interactions at the same time. In this report, we present critical new information for the National Cohesive Wildland Fire Management Strategy—a first-time CONUS-wide assessment of observed and potential wildland fire impacts on surface water yield. First, we analyzed data from 168 fire-affected locations, collected between 1984 and 2013, with machine learning and used climate elasticity models to correct for the local climate baseline impact.
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In this report, we identify and characterize scientific literature produced by USGS scientists during 2006–17 that addresses topics associated with wildland fire science. Our goals were to (1) make the most complete list possible of product citations readily available in an organized format, and (2) use bibliometric analysis approaches to highlight the productivity of USGS scientists and the impact of contributions that the Bureau has provided to the scientific, land management, and fire management communities.
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Biochar is a modern technology that returns carbon to the soil in the form of long-lasting charcoal. It’s made by baking biomass (such as tree wood, plants, manure, and other organic materials) without the oxygen that could cause it to burn completely to ash.
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Our model-informed decision framework illustrated that forest management (thinning and continued prescribed fire) was most effective and critical under extreme fire weather conditions. Using a model to inform on where high-severity fires were most likely to occur allowed for the strategic placement of management prescriptions, which reduced the amount of area requiring mechanical thinning and were just as effective as less strategic approaches in reducing wildfire severity.