Unable or unwilling to see, understand, or focus on a situation in its entirety due to being preoccupied with minor details. ("Wood" in this usage is a synonym for "forest.") I just feel like he hasn't been able to see the wood for the trees on this project, getting hung up on the most mundane details at the expense of our overall productivity. If you really can't tell that the president's actions are all working toward the greater good of the country, then you're just not able to see the wood for the trees.