Research and Publications
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This study investigated the relative importance of site productivity and seasonal climate in explaining the variance in recovery time for 36 fires, comprising a fire chrono-sequence (from 1971 to 2007) for the Great Basin and Colorado Plateau. A. t. vaseyana recovery was positively related to precipitation in the cool season immediately following fire, likely because deep soil-water recharge that persists throughout the growing season enhances first-year seedling survival. Percentage sand fraction positively correlated with recovery rate yet negatively correlated with live cover in unburnt stands. Our data support the hypothesis that post-fire recovery rate of A. t. vaseyana depends on the climatically controlled ephemerality of the regeneration niche, as is likely true for many arid-land shrub species.
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This study examined bark beetle mortality for two-years after fuel reduction treatment in mid-elevation mixed conifer forests at the University of California Blodgett Research Forest. As part of the National Fire and Fire Surrogate Study, the experimental treatments included prescribed fire (fire), mastication, the combination of the two, and a control.
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This study found that:
- Few changes in most of the measured masticated fuel bed properties were detected over the 10 years represented in the sample. This indicates that in dry environments, it may take at least 10 years for ecological processes to change fuel characteristics enough for adverse fire effects to be mitigated.
- Burning masticated fuel beds in a laboratory revealed that there is a great deal of heat that is pulsed into the soil that could cause major mortality to belowground systems. This is especially true in high loading fuel beds with duff layers present.
- All masticated fuel beds dried to equilibrium in less than seven days, indication that these quickly drying fuels can be readily susceptible to smoldering combustion after 5-7 days of drying.
- Existing fuel models (including 11, SB1, SB2 and two existing custom fuel models) were good at representing fire behavior, indicating that there is no need to develop new, custom fuel models for masticated fuel beds.
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The burnout time for upstream shrubs increased with an increase in shrub separation distance for all shrub sizes and wind speeds considered. The burnout time for the downstream shrub was found to decrease with an increase in the separation distance, reach a minimum, and then increase with an increase in separation distance. The trends observed in burnout times for downstream shrub were attributed to the balance between heat feedback into the downstream shrub from the flames in upstream shrubs and availability of sufficient oxygen for combustion to take place.
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The significant variables for the fatal injury model were fire shelter use, slope steepness and flame height. The separation distances needed to ensure no more than a 1 or 5% probability of fatal injury, without the use of a fire shelter, for slopes less than 25% were 20 to 50 m for flame heights less than 10 m, and 1 to 4 times the flame height for flames taller than 10 m. The non-fatal injury model significant variables were fire shelter use, vehicle use and fuel type. At the 1 and 5% probability thresholds for a non-fatal injury, without the use of a fire shelter, the separation distances were 1 to 2, 6 to 7, and 12 to 16 times greater than the current safety zone guideline (i.e. 4 times the flame height) for timber, brush and grass fuel types respectively.
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Fire is a strong driver of changes in montane forest structure in California’s Sierra Nevada and southern Cascade mountain ranges, which provide much of the snowpack and associated water storage for the state of California. A recent study by Stevens presented one of the first direct investigations in California of how fire can influence snowpack depth.
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In 2004, the Communities Committee of the Seventh American Forest Congress, Society of American Foresters, National Association of Counties, and the National Association of State Foresters sponsored and developed a handbook entitled Preparing a Community Wildfire Protection Plan. (Communities Committee of the Seventh American Forest Congress; Society of American Foresters; National Association of Counties; National Association of State Foresters, 2004) This guide is intended to supplement that handbook, with special considerations for local fire service leaders in communities identified as at-risk of wildfire. While adjacency to public lands (forests, brushlands and grasslands) can impact wildfire risk, there are ways to impact and reduce wildfire risk from within the community as well. This includes a focus on local codes and ordinances, home ignition Zones, defensible space, ignition-resistant construction and design standards, as well as hazardous fuels reduction in parks, common-owned areas, and open spaces within the local jurisdiction.
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In North America, decisions about how and when to apply prescribed fire are typically based on the historical-fire-regime concept (HFRC), which holds that replicating the pattern of fires ignited by lightning or preindustrial humans best promotes native species in fire-prone regions. This study found that the practice of inferring historical fire regimes for entire regions or ecosystems often entails substantial uncertainty and can yield equivocal results; ecological outcomes of fire suppression are complex and may not equate to degradation, depending on the ecosystem and context; and habitat fragmentation, invasive species, and other modern factors can interact with fire to produce novel and in some cases negative ecological outcomes. Although the HFRC is a valuable starting point, it should not be viewed as the sole basis for developing prescribed fire programs. Rather, fire prescriptions should also account for other specific, measurable ecological parameters on a case-by-case basis.
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In this paper, optimization models successfully identified areas with low conifer canopy cover, high resilience and resistance to wildfire and annual grass invasion, and high bird abundance to enhance sage-grouse habitat. The inclusion of mesic resources resulted in further prioritization of areas that were closer to such resources, but also identified potential pathways that connected breeding habitats to the late brood-rearing habitats associated with mesic areas. Areas identified by optimization models were largely consistent with and overlapped ongoing conifer removal efforts in the Warner Mountains of south-central Oregon. Land ownership of preferential areas selected by models varied with priority goals and followed general ownership patterns of the region, with public lands managed by the Bureau of Land Management and private lands being selected the most. The increased availability of landscape-level datasets and assessment tools in sagebrush ecosystems can reduce the time and cost of both planning and implementation of habitat projects involving conifer removal. Most importantly, incorporating these new datasets and tools can supplement expert-based knowledge to maximize benefits to sagebrush and sage-grouse conservation.
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This report identified leks and larger scale populations in immediate need of management, based on the occurrence of two criteria: (1) crossing of a destabilizing threshold designed to identify significant rates of population decline at a particular nested scale; and (2) crossing of decoupling thresholds designed to identify rates of population decline at smaller scales that decouple from rates of population change at a larger spatial scale. This approach establishes how declines affected by local disturbances can be separated from those operating at larger scales (for example, broad-scale wildfire and region-wide drought). Given the threshold output from our analysis, this adaptive management framework can be implemented readily and annually to facilitate responsive and effective actions for sage-grouse populations in the Great Basin. The rules of the framework can also be modified to identify populations responding positively to management action or demonstrating strong resilience to disturbance. Similar hierarchical approaches might be beneficial for other species occupying landscapes with heterogeneous disturbance and climatic regimes.