Agriculture Reference
In-Depth Information
a
b
d
c
16 000
14 000
12 000
10 000
8000
6000
4000
2000
0
Year
Fig. 7.11
Mean area burned per annum for 5-yr periods in the Swartberg Mountain range under
different management regimes. The year indicated is the last year in the 5-yr period.
Management policy: (a) burning for grazing (b) fire exclusion and suppression (c) prescribed
burning in “blocks” separated by a network of fire breaks, (d) natural fires. Graph modified
from Seydack
et al. (
2007
),
who attribute the periodicity in area burned to: less burned area,
cool moist periods during which fuel accumulates; more burned area, warm drier periods with
convectional (lightning) summer storms. Total area of the Swartberg study region is 170 856 ha.
The limited degree to which fires can be managed in mountain fynbos is also
evident in a recent analysis on the causes of fire in the Cape Nature data set across
the Cape region. Southey (
2009
) analyzed cause of fire for four regions, including
the Swartberg, between 1970 and 2007. Prescribed fires ignited by managers
accounted for 3 (Swartberg), 6 (Cederberg), 7 (Hottentots-Holland) and 15%
(Outeniquas) of the total area burned. Yet despite these low levels of management
control over area burned, apparently fynbos fires can be managed quite effectively
to protect people and property.
The Urban Interface
Economic damage caused by wildfires at the wildland-urban interface seems to be
far less than fires in California and the Mediterranean Basin (e.g. Spain, Greece).
For example, two severe fires occurred in the Cape Peninsula in January 2000 on
the urban fringe, burning a total of 8000 ha. Homeowners were evacuated and
there was general panic. Although these were among the most severe fires that
have been recorded at the fynbos WUI, only eight structures were destroyed and a
further 51 damaged. No lives were lost. Initial press reports estimated insurance
claims of US$500 million and suppression costs in the region of US$3 million
(Calvin & Wettlaufer
2000
). However, a subsequent government-commissioned
report listed insurance claims as
$5.7 million with suppression costs in the
region of $500 000 (Kruger
et al.
2000
). The relatively low damage to lives and
∼
