Q: Due to Hurricane Irma, one of our dogwoods split and came down. Will the rest of the remaining tree now get insect or other damage? Should we just take it down?
A: You are right to be concerned. It’s very likely that the hole in both tree trunks originated from a limb that broke off or was pruned improperly.
A stub left on a tree trunk inevitably rots away and allows water inside the tree. The water encourages rot that slowly progresses down the trunk and weakens it. That said, your inclination might be to drain the hole in the maple tree. However, research has shown that drain holes lead to faster rotting, not slower.
When pruning a tree limb it’s important to make the cut just beyond the collar where a limb goes into the trunk. This is a fast growing area that soon seals the wound and doesn’t allow water into the trunk. I can see that on your maple tree it tried to seal the wound but it was so large that water got into the tree trunk and has started moving downward.
It’s hard to know what to do in this situation. One gardener I know fashioned a tin roof to go over a large hole in her tree trunk. She attached the roof to the trunk above the hole with caulk. This allowed free movement of air in and out of the hole but prevented rain water from flowing into it.