We have a 35-40 foot oak that is rather thinly branched(most of the growth is at the top 10 feet), lots of dying lower branches(15-25 feet up). During the srping/summer it will have full leaves, but each year it seems that the tree is not as stout as it should be. The trunk(approx 24-30" diameter) has developed a split in the bark that runs from the ground up 3-4 feet. There are tiny holes (1-2 mm) in the trunk where the bark has peeled away. The tree commands nearly all the sun and gets plenty of water, though the soil may be lacking in nutrients. Clay is the norm in Central Illinois. Any ideas?
