| Forest Fires | 
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Wolffsohn (1967) suggested that about once
in every five or ten year the dry season in Belize is intense
enough to create hazardous conditions. The vegetation is
generally too damp to burn easily. This is especially the
case in "real" rainforest but evidence of rainforest
fires (dating many thousands of years back) has been collected
throughout the tropics (Bassini & Becker, 1990; Horn
& Sanford, 1992). Many of these large fires show a relation
to human presence and it is often assumed that early man
was directly or indirectly responsible for these fires (Horn
& Sanford, 1992).
It is generally accepted that once every one
or two centuries a series of abnormally dry years without
rainy seasons dramatically increase the fire hazard on otherwise
fireproof tropical rainforests (Jacobs, 1988). There are
indications that the incidence of rainforest fire is on
the increase worldwide. In 1982, 1983, 1992, 1993, 1997,
1998 and 2000, large surfaces of rain forest burned throughout
the tropics. This increase is most likely caused by increased
human encroachment on the forest and by the phenomenon of
global warming (which is expected to lead to more erratic
weather patterns including more frequent droughts). This
is especially worrisome since these wildfires are gaining
importance to the volatilization of gasses such as N2, N20,
CH4, CO2 and other greenhouse gasses, i.e. those that contribute
to global warming (Lugo, 1995).
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Fires are most devastating on hills where
an upward draft creates extremely hot fires towards the
top of the hill. Fire affected hills; therefore, show the
greatest damage towards the summit. Repeated hill fires
result in "bald" hills with no woody vegetation
but a cover of grasses or "Tigerbush" (the ferns
Dicranopteris and Pteridium caudatum).
The influence of fire is clearly greatest where there is
drought stress and highly inflammable vegetation is present.
Fire induced vegetation in hilly areas
are especially at risk since the fire resistant vegetation
has a lesser capacity of retaining the soil and increased
erosion is the result (Jacobs, 1989).
In the early days of the Forest Department it was noted
that fire kept broad-leaved forest species from invading
and replacing pine on soils which otherwise might have
carried high forest. Nevertheless, pines are liable
to be killed by fire when they are less than 3 m tall
and are liable to damage at any age and size. The old-growth
pines on the Southern Coastal Plain are frequently fire-scarred,
internally and externally. The damage allows the ingress
of wood-rotting fungi and termites and materially reduces
the net yield (ODA, 1989).
Data from the Forest Department over the period
1963-1970 for the hills of the Mountain Pine Ridge Forest
Reserve (Cayo district) indicate that out of 46 recorded
fires during that period, 29 (63%) were reported to have
been caused by lightning. The remaining 17 fires (37%) were
caused by human agency. In the northern Coastal Plain of
Belize, the great majority of the lowland fires are caused
by arson, by hunters after game (ODA, 1989, pers. obs.).
In contrast, in the pine barrens of Florida, lightning strike
is a frequent cause of fire (Lugo, 1995).
The combination of infrequent lightning strikes
and a degree of fire adaptation in the savannah and needle-leaf
community indicates that fire is a natural part of the Belizean
savannah ecosystem, probably helped by the droughtiness
of the vegetation and naturally occurring more frequently
than in broadleaf forest. That said, the natural savannahs
would be much smaller in extent and not burnt so often as
is presently the case.
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