Convective instability can influence the behaviour of large wildfires. Because wildfires modify the temperature and moisture of air in their plumes, instability calculations using ambient conditions may not accurately represent convective potential for some fire plumes.
Results from a laboratory-scale investigation of a fire spreading on the windward face of a triangular-section hill of variable shape with wind perpendicular to the ridgeline are reported. They confirm previous observations that the fire enlarges its lateral spread after reaching the ridgeline, entering the leeward face with a much wider front.
While many ecosystems depend on fire to maintain biodiversity, non-native plant invasions can enhance fire intensity, suppressing native species and generating a fire–invasion feedback.
The widespread, native defoliator western spruce budworm (Choristoneura occidentalis Freeman) reduces canopy fuels, which might affect the potential for surface fires to torch (ignite the crowns of individual trees) or crown (spread between tree crowns). However, the effects of defoliation on fire behaviour are poorly understood.
Mass media images of raging crown fires have affected how many people view their wildlands. Flames surge and leap dozens and even hundreds of feet into the air; planes zoom above the flames releasing streams of brightly colored retardant; and giant pyrocumulonimbus clouds tower over the landscape. No doubt, it’s dramatic lead story material.
Fuel treatment effectiveness is often evaluated with fire behavior modeling systems that use fuel models to generate fire behavior outputs. How surface fuels are assigned, either using one of the 53 stylized fuel models or developing custom fuel models, can affect predicted fire behavior.
Mastication is an increasingly common fuels treatment that redistributes “ladder” fuels to the forest floor to reduce vertical fuel continuity, crown fire potential, and fireline intensity, but fuel models do not exist for predicting fire behavior in these fuel types.
Seasonal changes in the climatic potential for very large wildfires (VLWF ≥ 50,000 ac ~ 20,234 ha) across the western contiguous United States are projected over the 21st century using generalized linear models and downscaled climate projections for two representative concentration pathways (RCPs).
Joint Fire Science Program (JFSP) project 09-S-03-1 was undertaken in response to JFSP Project Announcement No. FA-RFA09-0002 with respect to a synthesis on extreme fire behavior or more specifically a review and analysis of the literature dealing with certain features of crown fire behavior in conifer forests in the United States and adjacent regions of Canada.
This publication provides an overview of how various silvicultural treatments affect fuel and fire behavior, and how to create fire-resistant forests. In properly treated, fire-resistant forests, fire intensity is reduced and overstory trees are more likely to survive than in untreated forests. Fire-resistant forests are not “fireproof” – under the right conditions, any forest will burn.