Holes, hollows and cavities in tree trunks and branches make great homes for wildlife. They may, however, be a reason for concern when they occur on the trees in your landscape.
Tree cavities are typically the result of decay that occurs after a tree is injured. Improper pruning cuts, topping of trees, storm damage or injuries to the tree’s trunk are often the cause.
Trees often produce sufficient healthy wood around the cavity to support the tree and continued growth. Don’t clean out the cavity or drill holes in the bottom of the hollow to allow water to drain. This can further spread the decay, damaging healthy portions of the tree.
If the tree is near a building or areas used by people, have it checked by a certified arborist. They have the training and equipment to determine if the tree is safe and strong enough to remain.
A bit more information: Find a certified arborist in your area at the Trees are Good website. These professionals have experience, demonstrated their knowledge by passing the International Society of Arboriculture certification exam and maintained their certification through continuing education.