Abstract:
Successful implementation of projects under the REDD+ mechanism, securing
payment for storing forest carbon as an ecosystem service, requires quantification of
biomass. Airborne laser scanning (ALS) is a relevant technology to enhance estimates of
biomass in tropical forests. We present the analysis and results of modeling aboveground
biomass (AGB) in a Tanzanian rainforest utilizing data from a small-footprint ALS system
and 153 field plots with an area of 0.06–0.12 ha located on a systematic grid. The study
area is dominated by steep terrain, a heterogeneous forest structure and large variation in
AGB densities with values ranging from 43 to 1147 Mg·ha −1 , which goes beyond the range
that has been reported in existing literature on biomass modeling with ALS data in the
tropics. Root mean square errors from a 10-fold cross-validation of estimated values were
about 33% of a mean value of 462 Mg·ha −1 . Texture variables derived from a canopy
surface model did not result in improved models. Analyses showed that (1) variables
derived from echoes in the lower parts of the canopy and (2) canopy density variables
explained more of the AGB density than variables representing the height of the canopy.
