In American English, "he can't see the forest for the trees" means that he is so focused on minute details that he cannot understand the big picture. It loses all meaning if it is reversed.
It is also interesting to note that in Britain, "wood" meaning "forest" is singular, whereas in America it is "woods" (plural).
BrE: You won't be able to find him in that wood.
AmE: You won't be able to find him in those woods.