The bark often splits above and below poorly healed branch stubs. These splits are additional entry points for trunk-infecting microorganisms. Hollows Water often fills the hollows associated with very old branch stubs. Do not bore a hole to let water out of a hollow, because this will permit decay to spread into the healthy wood that surrounds the hollow. Prune old dead stubs properly.
Many microorganisms use old dead stubs as springboards into the trunk.
When a tree top is broken, prune the broken top. A vigorous branch near the broken top usually becomes the new leader. When pruned properly, the tree will heal its wound faster and the likelihood of decay developing decreases. If decay does develop, it is usually limited to the old leader. If cut when it is still small, its wounds will heal faster and decay will not start.