Question
My neighbor came by the other day concerned about a subject tree with damage and belief of it's dying and fears of falling down.  The tree has bark splitting on one side from near the base up a few feet. They mentioned a tree service individual (don't know of his qualifications, name is not listed in google, wasn't in when I called) stating the tree has carpenter ant issues. Neighbor stated in a note to me "there was a colony of carpenter ants or something like that in the tree". "It will come down & is being killed". The tree otherwise appears fine to me, i.e. buds coming in, no limbs falling, not leaning etc. I and others I've asked don't believe the tree is in immediate need of removal.  What would would you recommend I do, most cost effective means of validating the tree's life and/or treatment?  I also took a few photos of the tree with my cell phone (5.0 pixel)....don't have downloaded on a computer but could send to an e-mail address. I don't want strife with my neighbor but do want the best for this beautiful tree.....borders our property but mostly on my side. My neighbor appears in a hurry to get this tree removed and an adjacent garden plot of sorts of theirs has me thinking there is an ulterior motive here. Thanks much in advance for any advice or professional input.

Answer
Carpenter ant nests are very common inside trees, especially older trees that are hollow or have a significant amount of dead limbs and branches. The nests are usually in rotted, decayed wood, although some nests may extend into sound heartwood in the center of the tree.

Carpenter ants in trees are not directly harmful to the tree. Control is not essential for the tree's health, as the ants are only taking advantage of an existing situation of soft, weak wood in which to establish their colony. Stress, mechanical injury, environmental conditions, disease or other insects are responsible for killing limbs or sections of the trees in which the ants are able to nest. Once injury has occurred, wood decay can set in if moisture is present; it is the wood decay that gives the carpenter ants the opportunity to colonize the tree. Carpenter ants use knots, cracks, holes and old insect tunnels to gain access to these areas. Carpenter ants nest in trees in one of two situations: 1) in rotted, decayed wood or 2) in the center heartwood section of the tree. In neither case are they harmful to the tree. There is no control needed unless the ants are getting into the house.

What sounds like has happened is a wound has developed in the bark of the tree and over time decay fungi has entered and is slowly decaying the woody part of the tree. When a tree is wounded a decay fungi can enter the woody cells. Over many many years the decay will spread and begin to hollow out the tree. The living cells of a tree are just under the bark and the fungi does not effect them. So in general a decay fungi will not effect the health of a tree except it the tree later years may weaken the trunk or limbs causing breakage. There is no way to control the decay fungi. As long as the foliage is green and full there is not problem with leaving the tree as is. Before the trunk will break you will see large limbs breaking off and these will be hollow. Just keep the tree growing healthy and it will be OK. I would fertilize the tree with 10-10-10 fertilizer about once every other year to aid in the health. Use 1 lb per inch of trunk diameter scattered around the tree and watered in good.