how to treat trees with wood borers
"Wood borers' generally refers to wood boring insects, which are generally very small, and are the larval stage of a beetle. They spend part of their lives inside trees, then make their way out and leave behind exit holes.
We are not seeing that in your photos. There are many insects, birds, wildlife etc. that naturally use tree cavities and bark crevices for protection or homes, usually without great harm to the tree.
How does the tree canopy look during the growing season? Full, green and with normal sized leaves? Peeling bark is not a good thing on most trees, but would represent limbs that are dead or dying and can be removed. If the trees are not healthy, are large and could endanger people or property if they were to fall, you need to act more quickly.
You best bet is to hire, not a tree cutter, but a certified arborist, who is a certified tree health specialist to do an onsite evaluation of your trees. You can search for one at www.treesaregood.org.
Here are some of our publications that may help you make decisions:
IPM:Shade Trees: https://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG61_IPM_Series_Sha...
How to Decide When to Remove a Tree: https://extension.umd.edu/learn/how-do-you-decide-when-remove-tree
Thanks so much for your timely and helpful response! We will hire an arborist to check things out.