Use of ALOS PALSAR and other satellite data for mapping tree cover and biomass classes in South African savannas and African forests

Manfred Keil(1), Michael Schmidt(1), Tanja Kraus(1), Ursula Gessner(2), Christian Hüttich(2) and Tobias Landmann(2)

(1) German Aerospace Center (DLR), Münchner Str. 25, 82234 Wessling, Germany
(2) University of Würzburg, Am Hubland, 97074 Würzburg, Germany


African savannas and woodlands are parts of the ecosystems which are strongly impacted by anthropogenic pressures on natural resources and in addition by climate change. During the last decades, human activities have strongly affected the natural composition of life forms, i.e. the herbaceous and woody cover proportions, for instance by deforestation, heavy grazing and land use changes. The remote sensing based classification and estimation of woody vegetation cover in relation to grass / forb vegetation and open soil is often impeded by seasonal influences. Especially in dry savanna systems, the signatures given by optical systems are heavily influenced by the rainfall history.

In the frame of the BIOTA Africa project, ALOS PALSAR data in the L-band are investigated in supplementation to the characterization by optical data, regarding vegetation cover and classes of above-ground biomass. Additional information is given by different polarimetric states (HH-Polarisation, HV-Polarisation), pronouncing different scatter processes. The examples of investigation cover especially areas of thornbush and tree savanna in Namibia and in addition of forest areas in Eastern and Western Africa.



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