cant see the forest for the trees

Cant see the forest for the trees is a phrase which is referring to seeing the big picture, or broader, more general situation. By saying that you cant see the forest for the trees, the meaning is that you cant go to the forest just for the trees as there is so much more to a forest than the trees. You must see the broader picture, in this case the forest, including the animals, insects, plants, flowers and everything else you can see in the forest aside from the trees.