Piling and burning is widely used to dispose of unmerchantable debris resulting from thinning in forests throughout the western United States. Quite often more piles are created than are burned in a given year, however, causing piles to persist, accumulate, and age on the landscape. The effects of burning piles of increasing age has not been studied. We examined the effects of time since construction (i.e., pile age, in roughly six month increments for two years) and burn season (fall and spring) on fuelbed properties, combustion dynamics, fuel consumption, and charcoal formation for hand-constructed piles in thinned ponderosa pine-dominated sites in New Mexico (n = 50 piles) and Washington (n = 49 piles). Piles compacted over time similarly for both study sites, losing approximately 15% of their height annually for the first two years following piling. Peak flame height decreased and the duration of flaming combustion increased with increasing pile age for both burn seasons in New Mexico, yet depended on burn season in Washington. Increasing fuel moisture and compaction reduced peak flame height and increased flaming duration modestly for both sites. Peak flame height was reduced 6–7 cm and flaming duration increased 0.9–2.3 min for every percentage increase in small fuel moisture. Similarly, peak flame height was reduced 4–5 cm and flaming duration increased 0.6–0.8 min for every percentage reduction in pile height. Fuel consumption was high, averaging 90% in New Mexico and 95% in Washington. Fuel consumption patterns differed between locations, however; fuel consumption decreased with age and was slightly higher for spring than fall burns in New Mexico, whereas, neither pile age nor burn season affected fuel consumption in Washington. Charcoal formation as a fraction of pre-burn pile weight averaged 2.8% in New Mexico and 1.2% in Washington, and was not affected by pile age or burn season. Fuel consumption and charcoal production were unaffected by fuel moisture or compaction levels at either site. Findings from this study will inform fuel and fire managers about the potential effects on fire behavior, fuel consumption, and charcoal formation of burning piles of different age in different seasons under different environmental conditions.
The Fire and Smoke Model Evaluation Experiment (FASMEE) is designed to collect integrated observations from large wildland fires and provide evaluation datasets for new models and operational systems. Wildland fire, smoke dispersion, and atmospheric chemistry models have become more sophisticated, and next-generation operational models will require evaluation datasets that are coordinated and comprehensive for their evaluation and advancement. Integrated measurements are required, including ground-based observations of fuels and fire behavior, estimates of fire-emitted heat and emissions fluxes, and observations of near-source micrometeorology, plume properties, smoke dispersion, and atmospheric chemistry. To address these requirements the FASMEE campaign design includes a study plan to guide the suite of required measurements in forested sites representative of many prescribed burning programs in the southeastern United States and increasingly common high-intensity fires in the western United States. Here we provide an overview of the proposed experiment and recommendations for key measurements. The FASMEE study provides a template for additional large-scale experimental campaigns to advance fire science and operational fire and smoke models.
Wildfire affects the ecosystem services of watersheds, and climate change will modify fire regimes and watershed dynamics. In many eco-hydrological simulations, fire is included as an exogenous force. Rarely are the bidirectional feedbacks between watersheds and fire regimes integrated in a simulation system because the eco-hydrological model predicts variables that are incompatible with the requirements of fire models. WMFire is a fire-spread model of intermediate complexity designed to be integrated with the Regional Hydro-ecological Simulation System (RHESSys). Spread in WMFire is based on four variables that (i) represent known influences on fire spread: litter load, relative moisture deficit, wind direction and topographic slope, and (ii) are derived directly from RHESSys outputs. The probability that a fire spreads from pixel to pixel depends on these variables as predicted by RHESSys. We tested a partial integration between WMFire and RHESSys on the Santa Fe (New Mexico) and the HJ Andrews (Oregon State) watersheds. Model assessment showed correspondence between expected spatial patterns of spread and seasonality in both watersheds. These results demonstrate the efficacy of an approach to link eco-hydrologic model outputs with a fire spread model. Future work will develop a fire effects module in RHESSys for a fully coupled, bidirectional model.
The practice of removing fire-killed trees from burned forests (or “postfire salvage logging”) has sparked public controversy and scientific debate when conducted on public lands in the United States. This review synthesizes the current scientific literature on the subject, providing an update to a 2000 literature review (PNW-GTR-486) and subsequent synthesis (PNW-GTR-776). Forty-three published studies are reviewed, summarizing ecological effects on wildlife, vegetation, fuels, soils, and other environmental variables. Several key themes emerge from the review and specific research topics for future study are suggested. An annotated bibliography is provided at the conclusion of the document.
The study explores use of the Ecosystem Management Decision Support (EMDS) System to standardize the process of allocating Management Areas for Fire Suppression Support (MASSs) in Catalonia, Spain. MASSs are defined as those areas in the landscape that change fire behavior, reducing the magnitude of the wildfire, and improve significantly fire suppression effectiveness/capacity. Considerations for allocating MASSs include high likelihood of large fires in the vicinity, potential for spread, proximity of the location to valuable resources at risk, proximity to adequate water supply, accessibility by mechanized means, and fuel management opportunities. The combination of accessibility, water supply and fuel management opportunities, when allocating MAASs, provide the minimum requirements to allow fire suppression actions, while improving effectiveness and safety levels. For these purposes, we combine the newest data available, outputs from fire simulators and expert knowledge to define a problem that could be solved using EMDS within a participatory planning framework. To support the fire suppression mission of the firefighting service in Catalonia, this study uses a combination of strategic and tactical solutions, in which the strategic solution identifies high priority locations within the landscape for fire suppression activities, and tactical solutions identify high priority management activities within specific locations.