Figure 8 shows the distribution of [[sigma].sub.v], along with [Z.sub.H], for the Mount Bolton fire from 1515 to 1545 AEDT when the
crown fire and spotting dominated the fire's behavior (Fig.
Regions sensitive to
crown fires cover about 17% of Maamora forest (Table 15).
Dropping water or fire retardant ("slurry") from helicopters or airplanes ("slurry bombers") can occasionally return a
crown fire to the surface, where firefighters can control it, and can be used to protect individually valuable sites (e.g., structures).
Assessing
crown fire potential by linking models of surface and
crown fire behavior.
In order to establish three replicates of three patch sizes that differed in size by an order of magnitude, we selected a small (1 ha), moderate (70-200 ha), and large (500-3600 ha) patch of
crown fire at each of three geographic locations (Table 2) across the subalpine plateau (Fig.
In contrast to the absence of
crown fire in the two panhandle stands, fire has been important in the two peninsular stands.
Decreased fire importance is consistent not only with model predictions of a more positive water balance and rising temperatures (Kutzbach and Guetter 1986) and presettlement analog comparisons suggesting stands where
crown fire is uncommon (Clark et al.
About 35 years later I experienced another running
crown fire, this time for real.
In one case, extreme winds descending from a thunderstorm blew across the A-rock blaze with gusts of 60 miles per hour, propelling a
crown fire through 2,000 acres of forest that had previously burned during prescribed fires.
Figure 2 shows that 8 years and more after fuel reduction, the treatments are still projected by fire models to greatly reduce the chance of a
crown fire compared to untreated forest.
Open-grown fir branches become fuel ladders that can feed a dangerous
crown fire. In the future, encroaching Douglas fir saplings invading oak savannas can be safely managed by prescribed and controlled burning.