Q: I have an 80 year old Oak Tree which I had a 22 inch limb removed that was hanging over my garage. There is a 3-4 inch hole in the stump at the severed part at the main tree trunk which was caused by ants.

There were some ants dormant in one of the cut up sections of the limb but evidence in six or seven other sections. I had it cut for fire wood and found the ants when splitting the sections. What do I do with the hole going into the tree and how would you recommend general care of an Oak regarding ants in general.

The tree guys thought that the tree looked in general good health. Several year ago I took down another tree and it was full of ants which I destroyed and have used hardware store ant poison products around the house and remaining tree and have not seen any excess ant population.

A: If the hole in the center of where the limb was cut off is not too large in diameter (no more than 2/3 of the whole diameter), and it doesn't extend too far into the tree (like into the trunk are itself), then it's probably OK, but it's hard to tell for sure without seeing it.

Many times you can find interior decay within a limb once it's been cut off, and as long as there is sufficient sound wood around its perimeter, there's no significant loss of strength.

I personally wouldn't fill the hole with anything, but you can, if you like, get an aerosol can of insulation and fill the hole that way. Let it expand beyond the edges of the hole, then carefully trim off the excess.

As to your ant situation, ants typically do not cause problems in trees. They are there simply because a decay situation was already in place, and they exploit it by cleaning out the decayed wood (which is why you find sawdust beneath the tree) to make galleries into which they place their eggs.

They generally only chew on decayed wood, so they really aren't harming the tree since decayed wood does nothing good for the tree.

In fact, ants are a good diagnostic tool -- if I see sawdust beneath a tree but I can't find a cavity, I know ants are working somewhere inside and it tells me to look further -- there may be enough decay hidden within that there is significant strength loss.

As for controlling the ants, you really don't have to. Since they aren't doing any harm, they can be left alone. Just keep them out of the house, where they're unwanted.

Decayed and/or hollow trees can be 100% alive but 90% hollow so, like they say, looks can be deceiving.

If there is ever a question about structural integrity, always enlist the services of a competent arborist to investigate it for you.