[alisson]

The natural habitat of Cocoa tree as usually bellow other trees, like many other species, Coffee too, it likes to be a little shaded by others, and the main thing about this method shown in the videos is very regular pruning and by organizing the organic matter in the ground the nutrients gets available for other species as well as more sunlight, so making very good use of the ecological succession - soil gets better and better naturally with nature processes - which is something very well known and studied in Botany but very little applied to agriculture, this is the gap this farmer is filling. As shown a little in the video, when he's going to grow something very sun hungry like lettuce or corn he does that by opening a big area in the forest and together with the lettuce he introduces seeds of other trees for the next natural succession.

I don't have an actual verified study to show you :/ But I believe there are a bunch of studies, as I have seeing a few universities making them, but I don't know how to find them. All I have now is my own experience on this topic.