A tool for monitoring woody biomass (change) in woodland ecosystems

Changes in forest area, forest biomass and related carbon emissions are altering the global carbon cycle. Knowledge of the magnitude, location and causes of forest carbon stock changes is crucial to achieving sustainable forest management. In this paper we present the Biomass Assessment and Mapping Tool (BATMAP), which was first developed over a woodland forest area of 1,160 km² located in central Mozambique, where an inventory of ninety-six plots was used to calibrate L-band high resolution radar data (ALOS PALSAR). Biomass maps were generated and carbon stock quantified with per-pixel random errors of 10 MgC ha^-1 and scene-wide bias of 1.6 MgC ha^-1 (95% confidence intervals) over a three-year period between 2007 and 2010. To investigate the tool´s versatility in assessing woody carbon stocks and their change in similar African woodland ecosystems, two case studies were investigated, in collaboration with LTS International Ltd. The first project involved assessing the effects of degradation in the middle Shire river basin in Southern Malawi. Degradation accounted for more than 36% of the total biomass loss, illustrating the important role of degradation alongside deforestation in woodland landscapes. The objective of the second project was to test Batmap on different forest ecosystems, which confirmed the importance of site-specific parameterisation of the tool.