Flagstaff
Interface Treatment Prescription
Results
in the Wildland/Urban Interface
Historical
Trends
Prior
to European settlement in the 1860's, the forest was
comprised of relatively open stands of large-diameter
ponderosa pine. Tree numbers averaged 30-50 per acre, with
these trees arranged in small groups. While some young thickets were undoubtedly present,
a savanna grass-land dominated the landscape. Fires were frequent, returning every 2-7 years,
and were relatively low-intensity in nature.
By
the 1880's, the forests were subjected to intense livestock
grazing and timber harvesting. The removal of most of the grass, coupled with
a period of relatively wet weather and the exceptional
1919 cone crop, saw many new seedlings established. For most of the 20th century, a policy
of active fire suppression - almost to the point of
fire exclusion - was embraced and practiced.
As
a result, many of the pine stands are presently overstocked
with small and mid-sized second-growth trees. Basal areas commonly range from 150 to well
over 200 and tree density from several hundred to a
few thousand per acre. Canopy closure typically varies from 50 to
70% but often approaches 100%. An occasional juniper, pinyon pine, Douglas fir,
white fir, Gambel oak, limber pine or aspen occurs among
the pine stands. Insect
and disease problems in these stands include dwarf mistletoe
and periodic episodes of various bark beetles.
Sites
are best represented by Fire Behavior Prediction System
(FBPS) Fuel Model #9 - closed-canopy pine stand with
needle understory. In the few open areas, the ground cover is a
mix of grasses and forbs. Heavy logging slash from the early 1900's such
as pitchy high stumps and cull trees contribute to the
fire hazard and laddering potential.
Goals
Generally,
the goals are four-fold:
1.
Reduce the wildfire hazard through a combination of
thinning, brush disposal and prescribed fire.
2.
Maintain and enhance vegetative species and structural
diversity of the site.
3.
Improve overall forest ecosystem health. |
