Question
I live in Texas and have two beautiful oak trees in my front yard.  Last summer was very hot and dry.  I did not notice until recently that one of the trees has a 4" by 3ft crevice on it's sdie.  There were ants inside, red ants.  I sprayed the ants with a general bug killer.  I also noticed that there was a slight discharge coming out of the bottom of the crevice.  I am worried and don't know how to fix this problem  The ants are not bothering it sinve I sprayed.  HELP!

Answer
If the foliage is green and healthy looking do not worry about the "crack". Sounds like the tree has a rot inside the trunk. If a tree is damaged a fungus can get into the tree and grow slowly rotting the inside and will over a long time make tree hollow. Not really a problem for the health of the tree. The living part of the tree is just under the bark called the cambumiun layer of cells. The inside cells (wood area) are acually dead and if the bark is damaged fungi can enter and start to eat away the dead cells. I would spray this area about every three months with an insecticide for borers to keep these insects from attacking the weak spot on the trunk. Check with a local garden/ nursery type store and ask for an insecticde for borers. If you see any other insects such as ants control them at that time. Over all if the foliage is green there is no problem with the tree dying.