Agriculture Reference
In-Depth Information
highly successful at nearly eliminating fires, and thus fire suppression can be
equated with fire exclusion for much of the twentieth century. However, as the
North American TV newsman Eric Sevareid was fond of saying, “Most problems
begin as solutions” and this well describes the success story with fire suppression in
western North American forests. After a century of fire exclusion, fuels have
accumulated sufficiently to shift the fire regime from a surface fire to a crown fire
regime. A similar situation appears to be true of montane conifer forests in the
Mediterranean Basin (Fule´
et al.
2008
).
Prescription burning was routinely used during the first 70 yrs of the twentieth
century in California as a means of “range improvement,” which consisted of
repeated burning for the purpose of converting shrublands to alien-dominated
rangelands (Keeley & Fotheringham
2003a
). Subsequently, prescription burning
was widely advocated as a means of reducing hazardous fuels, but the close
juxtaposition of wildlands with urban populations has proven too dangerous
and it has all but been abandoned in coastal and foothill shrubland landscapes.
However, it is widely utilized in montane conifer forests due to the remoteness of
the localities and greater ease of controlling understory surface fires. Long-term
repeated applications appear to have been highly successful at restoring historical
fire regimes, at least in localized areas (e.g. Keifer
1998
).
In central Chile landscapes surrounding major metropolitan areas have had a
long history of intensive land management that has reduced fuel loads and fuel
continuity, making catastrophic wildfires less threatening. In central Chile essen-
tially all fires are anthropogenic although lightning is a source of ignitions further
south. With increasing production of pine plantations in the southern part of the
MTC region has come the potential for high-intensity crown fires that threaten
timber resources. National efforts at fire prevention and fire suppression are
focused on reducing destruction of resources such as these.
Fire suppression policy in the MTC Western Cape of South Africa was begun in
the first half of the twentieth century and continues to the present. This is justified
because of the growing populations and increasing anthropogenic ignitions,
coupled with evidence that fires are more ignition dependent than fuel dependent
in this region (van Wilgen
et al.
2010
). Increased human ignitions in mountains
surrounded by urban areas have burned through younger fynbos stands more
often than historically was the case, changing the fire return interval from 38 to
13 yrs and threatening slower maturing plants (Forsyth & van Wilgen
2008
).
Nonetheless, in the 1970s prescribed burning programs were initiated in mountain
catchment areas, for purposes of protecting forests, watershed cover and reducing
alien plant invasions. Since the mid 1980s, the areas burned in prescribed fires
have declined, linked to changes in state agencies managing the land and a decline
in financial and human resources for prescribed fires. Prescribed burning has also
become more difficult, especially near the urban-wildland interface, because of
issues of legal and financial liability.
In more remote areas of the Cape region, prescribed burning has been replaced
by natural fire zones in which attempts are made to suppress anthropogenic fires
