Yeah, it should be "fell the tree".
-anguka = to fall
-angusha = to fell, to make fall, to drop (it's the causative version of anguka)
Theoretically speaking, could it also mean "drop the tree", as in from a crane or similar apparatus? Or do we find ourselves restricted to the meaning of "fell the tree" (which it should be)?
It sounds not right to me. I think of angusha to mean drop something. Theirs sounds like direct translation
I agree -angusha is often used in the context of dropping something. Still I think "fell a tree" is probably OK, because I find other instances of "kuangusha mti" online. In everyday American English we very rarely talk about "felling" trees. It would be "cut down the tree" or "cut the tree down", "chop down the tree (if with an axe)" or maybe just "cut the tree."
fell  v[erb] t[ransitive] - angusha; kata (mti)