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
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.
The goal of the burn is to use prescribed fire to reduce the density of ponderosa pine forest, the pion and juniper woodland, and hazardous accumulations of vegetation that under the right conditions could contribute to high intensity crown fire
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.