The Use of Remote Sensing in Defining and Assessing the Wildland Fire Regime and its Impacts on Forests and Range Management

Abstract

Although wildland fire occurs on a large scale in Sudan, there is limited knowledge on its extent, seasonality and frequency. Consequently its impacts on the environment are not well understood. The overarching objective of this study is to contribute in finding and recommending measures leading to minimize the adverse impacts of wildland fire on the environment in Sudan. This objective is investigated in the Albaja region of Sudan, which is chosen as a demonstration area representative of Sudan’s marginal grassland. To address the objective in Albaja, the study integrates both biophysical and social survey data collected in the field with remote sensing data from the MODIS (MOderate Resolution Imaging Spectroradiometer) sensor. MODIS remote sensing data is analysed for the 2000-2005 period to discover Albaja’s fire regime (extent, seasonality and frequency of burn). This new, satellite-derived information on burning in Albaja is then used to assess the effectiveness of the local fire management system that is currently applied to control wildland fires. The impacts of wildland fire frequency on trees, shrubs and grasses is then investigated by analyzing the satellite-derived fire data in conjunction with data collected in a vegetation cover survey carried out in Albaja in 2005. The study also combines MODIS vegetation index data with field measurements of herbaceous biomass in order to produce a spatially explicit map of end-of- wet-season biomass across the study area. Finally, a questionnaire survey with local farmers and nomads is used to investigate the different causes of wildland fire. The investigation reveals that on average 40% of the Albaja study area burns every year. It also reveals that the currently applied fire management activities do not control wildland fires and makes VII recommendations to make these activities more effective. The study also concludes that the repeated wildland fires are negatively affecting the existence of the most valuable trees, shrubs and grasses, which subsequently reduces the range carrying capacity of Albaja and hence increase the poverty of the local people and the nomads. The study also finds that the spatial configuration and quantity of biomass become predictable at the end of the wet season by correlating field measurement of aboveground dry biomass with time-integrated vegetation index values obtained from MODIS vegetation indices product. Field-calibrated remote sensing data therefore provides a new, practical basis to prioritize the construction of fire lines to begin in areas with high biomass that are at most risk of fire spreading out of control. The social survey finds that the main causes of fire are Careless cooking, Charcoal production and Poachers. The combined results highlight the importance of fire as a process that affects not only the biophysical environment but also exerts direct control on people’s livelihoods.