I'm a bit sleep deprived due to children, but the first thing that pops into my head is "primates like trees". I guess as a seed, we haven't fallen too far from that tree, so to speak.
In fact, primates like the intersection of trees and grasslands - open fields provide visibility, trees provide safety. ...not just for the primates, but for all sorts of smaller critters, which go by the name "food".
