menard mbende and his wwf team continue to gather data about the plant and animal world. and it is hot out here. >> here we're in the tree savanna. down on the river, there's riparian forest. we're now going to the forest to collect further data about the biodiversity, the flora, and biomass there. >> the counting is done within a precisely measured area. the researchers extrapolate that data about biomass to the entire forest. >> this is our predetermined area in which we examine the height of the trees, their circumference, and the color of the wood. we examine the entire biosphere and then compare that data with what comes from lidar. >> here, the forest is still intact, and there's a lot of biomass. that's good for the carbon dioxide footprint. but what the researchers are not finding is animals. this forest is as empty as the savanna that surrounds it. it's former residents have long since disappeared to the (bush)meat markets of the cities. >> time to leave congo now and fly some thousand kilometers to the northwest, were we touch down in the harbour town of douala.