Agriculture Reference
In-Depth Information
Agroforestry
Tree plantations of Monterey pine (
Pinus radiata
)and
Eucalyptus
cover an esti-
mated 2.5 million ha in Chile, with Monterey pine representing 80% of the total.
From a relatively small industry in the 1960s and early 1970s with about 6000 ha
of plantations added annually (Lara & Veblen
1993
), a massive expansion of this
industry now adds an average of over 70 000 ha of new plantation area annually.
Exports of wood chips and pulp from these plantations provide approximately
13% of the total Chilean exports. Chile is the world's third largest exporter of
wood chips and sixth largest of pulp.
About 60% of this area of tree plantations lies at the southern end of the
MTC region of Chile (Regiones VII and VIII). Most of the original areas of
these plantations lie in the coastal ranges, which had previously been deforested
and degraded by erosion (Estades & Escobar
2005
). As the total area of plantations
has increased, however, native sclerophyll forests have been cleared to provide
suitable plantation sites, which can produce more than 20 m
3
ha
1
yr
1
of wood
biomass.
Fire has been widely used in clearing native forests for plantations and
as a management tool in plantation forestry due to its low cost and ease of
implementation. Such fires have been shown to significantly affect some soil
chemical and physical properties, as well as plant species composition (Litton &
Santelices
2002
). The intensive silviculture utilized in managing Chilean planta-
tions predisposes them to forest fires (Lara & Veblen
1993
). These are single
species plantations (monocultures) planted in high density, and carrying a
large biomass of flammable dead fuels. Moreover, the coastal mountain ranges
are characterized by irregular topography with gullies and canyons that can act as
convective chimneys and greatly increase rates of fire spread.
Fire Management
Although it seems that fire has not played an important role in the recent
evolutionary history of the matorral shrublands of central Chile, fire has been
widely applied to the landscape for more than four centuries as an important
tool in agricultural and forest clearance (Armesto
et al.
2010
). Widespread
traditional views of land management using fire clearance and burning of agri-
cultural residues and logging slash has brought significant economic gains with
little attention given to possible environmental consequences. With the increased
numbers of fires in recent years (Table 6.2) and concern about their ecological
impacts, there has been an evolving program of improved fire management
objectives and protocols.
Over the last few decades there have been new laws enacted to control and
regulate the use of fire in forestry and agricultural activities, with significant
penalties for infractions. Controlled burning to eliminate vegetation cover is
