This study reports on two independent sources of environmental data, both collected by remote sensing observations (aerial and satellite). Satellite imagery provides consistent and contemporary data on areas that are difficult to survey by other means due to either their physical inaccessibility, their large extent, or their unfavourable political climate. Within mainland Southeast Asia, Cambodia is a case in hand. Presented here is an assessment of vegetation fire activity determined using 1 km resolution AVHRR data (Jones 1996a) in relation to land use and land cover at a 1:500,000 scale (UNEP/GRID 1995). It is apparent that fire mainly occurs within Cambodia's deciduous forest formations that occupy some 34% of the country. The majority (75%) of these fires occur between January and February when leaf fall is at a peak. Leaf senescence contributes both to a high fuel loading and allows a drying of the forest understorey. Adaptation of these seasonal forests to withstand fire activity is high. Dense broad-leaved forests occupy approximately one-quarter of Cambodia, 12% of fires were observed here. Many of these fires are assumed to be associated with timber extraction and land clearance for shifting cultivation. These activities commonly instigate a period of protracted forest degradation unless disturbance levels are within environmentally and ecologically sustainable limits. Fire density was highest within pine forest formations, seasonally flooded evergreen forest and grassland susceptible to flooding; all these land cover types occupy less than 5% of the country's land surface area. In contrast to deciduous forests, for most land use/land cover categories fire activity was greatest during the late-dry season period (March to April), reflecting a period of greatest fuel flammability and fire -setting activities by man. © 1998 Taylor & Francis Group, LLC.
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