Question
Hello Jim,

I live in deep south Texas and have many trees in my yard that have been damaged from storms over the years.  Most of the trees have hollow areas up and down the trunks but all appear very healthy.  I have noticed a variety of insects and ants going in and out of these hollow areas.  What can I do to insure these trees survive many more years.     Thanks

Answer
The heartwood consists of the growth rings in the center of the trunk. They are aged sapwood and thus form part of the Xylem. They tend to have a darker color than the sapwood, because they no longer transport any water and are therefore much drier, and they tend to be clogged up with gums, resins and other substances, depending on tree species. Because they are no longer taking part in the trees vital processes, they can be said to be 'dead wood'.

A hollow tree is a tree where the heartwood, which has less resistance to rot than the living parts, has gradually decayed away. Surprisingly, this makes no difference to the vigor of the tree and may even enhance it ability to stand up to severe gales, due to the immense strength of a tubular structure. So it is important to realize that a tree with decaying heartwood is NOT a decaying tree! It is a natural process in many older trees and makes them all the more valuable as a habitat for many different forms of wildlife.

The deacy is not effecting the living cells and really not effecting the health of the tree except if the decay expands up into the crown and large limbs start to fall which have hollow ends near the trubnk. In this case the tree may become a hazard if it were to fall on anything.

The insects are either feeding on the fungi or making use of the decayed wood to make nests. You can spray the hollow areas with an insecticide like Sevin and this will keep the insect away. Either way they realy are are  harming the tree.

I would fertilize the tree with 10-10-10  fertilizer at the rate of 1 lb per inch of trunk diameter scattereda around the tree and watered in good. Apply just before a rain strom and you will not need to water. This will help the overall health of the trees.