Agriculture Reference
In-Depth Information
fire-fighting activities such as backfires. As a consequence it is critical that stra-
tegic planning be a critical part of the process. Historically area treated has been
the measuring stick for level of success but the sheer volume of treated landscape
may not be the appropriate metric. Planning needs to consider where defensible
space is most likely to be available under scenarios representative of the extreme
fire conditions that generate the worse fire outcomes. One example of this
approach is in the fire management plan for the southern California Santa Monica
Mountains National Recreation Area (SMNRA
2004
). Their planning process
consisted of a serious of decisions about what landscape features comprised a
suitable site for defensive fire activities and coupled with other data layers to
generate the most strategic sites for fuel treatments. In general the plan pointed
toward treatments along boundaries of the park with the urban fringes, a man-
agement approach shared with some Australian parks (Whelan
2002
). Fuel treat-
ment is inherently expensive and rates of treatment need to be high to have major
effects. This boils down to the fact that we can only ever afford to intensively treat
smaller rather than larger areas. Control over fire is therefore only ever local
rather than global except where vegetation is permanently removed. Thus, it is
about optimizing what we can realistically afford and sometimes the costs can be
extraordinarily high for effective risk reduction (Bradstock
et al.
1998b
).
Wildland-Urban Interface Management
Historically there has been an inordinate amount of effort directed at solving the fire
problem by focusing on the wildland fuels; that is, efforts at affecting factors
I
and
S
in
Equation (13.1)
.Indeed,Cohen(
2008
) contends that a legacy of “an organiza-
tional mindset that persistently frames the wildland-urban interface fire problem in
terms of fire suppression and control” has hindered work toward more effective
alternatives in the urban environment. The history of fire control efforts in MTC
regions, particularly in Australia and California, make it clear that wildland prefire
fuel treatments and fire suppression cannot stop all fires from reaching the wildland-
urban interface. It is becoming increasingly evident that greater effort needs to be
focusedonfactor
E
, namely the probability of fire encroaching into the urban
environment. Fires encroach in two ways: the radiant heat of the fire front ignites
urban infrastructure (homes, fences, landscaping, etc.) or wind-driven embers (also
known as firebrands) land and ignite components of the urban infrastructure.
Under severe fire weather conditions it is apparent that reducing fire encroachment
into the urban environment is little affected by fuel treatments broadly distributed
across the wildland landscape; rather perimeter-based strategies may be far more
effective (Franklin
1987
; Bradstock & Gill
2001
). Even where forest fuel treatments
significantly altered fire behavior, there are examples where this was not sufficient to
prevent sizable losses of homes (Cohen & Stratton
2008
; Safford
et al.
2009
). Often-
times the problem is not as much with the forest fuels but with the urban fuels.
A significant amount of local preparedness for fires comes in the form of fuel
alterations to create a buffer zone around homes, what is sometimes referred to as
