Monitoring post-burn recovery of chaparral vegetation in southern California using multi-temporal satellite data

Monitoring the post-burn recovery condition of chaparral vegetation in southern California is important for managers to determine the appropriate time to conduct controlled burns. Due to the difficulty of monitoring post-fire recovery over large areas and the absence of detailed fire records in many areas, we examined the possibility of using satellite observations to establish the postfire recovery stage of chamise chaparral stands in this region. SPOT XS data collected on three dates between 1986 and 1992 were analysed to determine if temporal changes in a spectral vegetation index tracked the expected post-fire recovery trajectory of the above-ground biomass of chamise chaparral stands of varying post-fire ages. Results of the study indicated that neither the normalized difference vegetation index nor the soil adjusted vegetation index followed the expected post-fire recovery patterns in these stands. These findings are explained by interannual variations in precipitation having a larger than expected effect on the growth of this drought-resistant evergreen community, with changes in green leaf area dominating the temporal variations in the spectral vegetation indices.