dr. davies: our basic rearch program is to study large pieces of forest. we set up these research plots, which are 50 hectares in area, typically -- so that's a kilometer by half a kilometer -- in which we study every single tree species that occurs in those areas. we do it all one by one. we go out, we start at the corner of these big plots, and we tag and map and measure every tree bigger than a centimeter in diameter. that's as big as a little sapling in your garden. and we monitor everything. we have, in some of our research plots, more species of trees than the whole of north america or the whole of europe. that's a phenomenal number of species -- 1,000 species or 1,200 species in one plot. narrator: at 17 forest-dics plots throughout latin america, africa, and asia, davies' project, in collaboration with the arnold arboretum of harvard university, maintains an active database of more than 3 million trees of 6,000 species. dr. davies: this is a huge data set, which no one else in the world is doing this kind of research. and the idea of doing it right