BUSHFIRES IN THE KRACHI DISTRICT: THE SOCIO-ECONOMIC AND
ENVIRONMENTAL IMPLICATIONS
J.M. Kusimi?, J. W. Appati*
© Department of Geography & Resource Development, University of Ghana, Legon.
Email: jimkusimi@ug edu. sh
" Department of Geography & Resource Development, University of Ghana, Legon.
Working Group, Theme or Special Session: VIII/1: Disaster Management
KEY WORDS: Bushfires, Fire severity, Krachi District of Ghana, Normalised Burn Ratio, Remote Sensing, Change Detection.
ABSTRACT:
Bushfires are becoming one of the environmental challenges confronting Ghana and increasingly it has become difficult for the
Government to control it because this activity is deeply rooted in the socio-cultural and economic systems of the people. The effects
of bushfire on rural livelihoods and on the ecosystem in Ghana are extensive and damaging. Bushfires have accelerated
environmental degradation especially in the fragile savannah ecosystem, yet there is very little in the form of public education,
published data and information concerning the frequency, intensity, duration and effects of bushfire on the environment and human
welfare in Ghana. The study did a change detection of biomass cover using pre and post fire normalized burnt ratio of Landsat TM+
imageries of 2002 and 2003 to determine fire severity on vegetative cover. The socio-economic impact of this disaster was collected
using social survey approaches such as interviews and focus group meetings. Some of the consequences of the bushfire include the
burning of food stuffs, houses as well as domestic animals. The environmental impacts of these bushfires have been very devastating
and these involve the lost of biodiversity (plants and animals) and the depletion of organic matter of the soil thus impoverishing the
soils. The research found out that, the continuous prevalence of this activity was due to the laxity in the implementation of bye-laws
regulating bushfire burning due to the lack of personnel and logistics to state agencies in the District to combat the problem.
changes such as canopy consumption, ground charring, and soil
1. INTRODUCTION colour alteration that are associated with this disaster. Remote
sensing is a useful tool for mapping the extent of the burn,
Bushfires are a common occurrence in the savannah understanding the biological responses due to differential
ecological zones of Ghana. The savannah and grassland surface heating (i.e. fire severity), and quantifying the extent
environments produce fine fuels that dry out rapidly at the end and pattern of these burned areas (Eidenshink et al, 2007; White
of the rainy season resulting in some of the most frequent fire- et al, 1996). These physical characteristics are detectable using
return intervals on Earth (Archibald et al, 2010). Moreover, sensors that can capture these attributes of landscapes. Fire has
human ignition and fire management are pervasive throughout a significant effect on the reflective properties of the land
Africa, because much of the population is not yet urbanised, and surface due to vegetation removal, soil exposure, and soil colour
communal land management is common (Archibald et al, 2010). alteration making the observation of fire severity by spectral
Wild land fire is an ecologically important disturbance factor in data possible (Jakubauskas et al, 1990; Milne, 1986, cited in
many ecosystems. While providing many benefits in fire- White et al, 1996). Pre-fire vegetation conditions also influence
adapted systems, catastrophic fire can cause severe ecosystem spectral classification of burn severity (White et al, 1996) by
and watershed damage. Catastrophic fires modify ecosystems comparing it with post-fire conditions of the vegetation.
by removing vegetative cover, destroying leaf chlorophyll, Several algorithms to identify and map burned areas have
charring stems and altering soil characteristics which increase been developed (Miller and Thode, 2007; Miller and Yool,
the risk of severe erosion and the time required for ecosystem 2002; Roy et al, 2006), which give an indication of the total area
recovery (Epting et al, 2005; Miller and Yool, 2002). burned by fire, and can be used to derive the season and
Information on within-burn variability is useful to ecologists frequency of fire (Archibald et al, 2010). Indices applied to burn
and resource managers who want to understand fire's effects on mapping have included single date, post-burn and bi-temporal,
ecosystem processes, for example, vegetation recovery and pre- and post-burn approaches (Epting et al, 2005). Parameters
succession, and to plan post-fire rehabilitation and remediation. used to estimate severity in the field include the condition and
Such within-burn information may be estimated by visual colour of the soil, amount of fuel consumed, resprouting from
examination of burned site conditions or by labour-intensive burned plants, blackening or scorching of trees, depth of burn in
field measurements (Roy et al, 2006). the soil, and changes in fuel moisture. Although several of these
A number of approaches to the monitoring of biomass burning ^ parameters may not be amenable directly to optical wavelength
by remote sensing have been proposed over recent years (Eva remote sensing, or may not be related in a linear way to
and Lambin, 1998). The first option concerns the selection of a reflectance, field-based measures of fire severity have been used
suitable indicator of biomass burning: smoke plumes, active to parameterize and assess fire severity maps created using
fires; or burnt areas (Eva and Lambin, 1998). Remote sensing of optical wavelength satellite data (Roy et al, 2006). One index
burnt landscapes is made possible because of the physical presented as a reliable means to map fire severity using remote
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