Question
QUESTION: Jim,
We live in the coastal area of South Carolina and have numerous, very old (200 year range), huge (2 to 3 stories high), oak trees in our yard. One of the trees had a very large limb removed about 18 months ago by our area's local oak tree expert. It was healthy, just overhanging the roof of our house, and was removed just as a precaution before the house was placed on the market. Now it seems we have a fungus conk growing out of the tree about 6 feet up. We have been advised to do two things: 1. trim back the other large limbs on that side of the tree to remove some weight, as well as cable them (there is already cabling and lightning protection very high up, and 2. fertilize one gallon per every inch of tree diameter to promote more healthy growth. We are very paranoid about losing this tree as it is the focal point of our yard and absolutely massive. He does not indication that he would put chemicals on the tree to kill the fungus, nor does he want to fill it with any material if there are hollow spots. What advice can you give us before we undertake a rather expensive treatment for this precious tree? I do have photos if you have a way to receive them. Thank you.
ANSWER: Was the limb that was removed hollow or mussy or was the wood attached to the trunk solid? If the limb was hollow this would indicate that the decay fungi that seem to be growing in the woody part of the tree has grown up the trunk a distance. The conk is the fruiting body of a decay fungi. These fungi enter the tree through a wound and over many years can decay the inside woody cells of the tree. This can make the tree hollow. I would say that the decay fungi has decayed the wood up to at least the 6 foot level on the trunk.
This is not mean that the tree is a hazard and will fall at any time. trees can and do live many many years as hollow trunks. The decay fungi only infects dead cells and will not kill the tree. The strength of the tree may suffer over time--if upper limbs start to break and if these are hollow than the decay fungi has grown up into the crown and the hazard maybe the fallen limbs. There is a very low chance that the entire tree will fall over. Unless you are having large limbs break and these are hollow I would not cable or prune back the limbs. Pruning the limbs back can cause an entry point for more fungi.
I would fertilize the tree--I recommend that you use 10-10-10 fertilizer at the rate of 1 lb per inch of trunk diameter scattered around the tree and watered in good. IF you fertilize just before a rain storm you will not need to water. Do this now and again in the spring and then once a year.
I agree that decay fungi can not be treated with a fungicide. It is like a decayed tooth you would have to excavate all the decay down to good wood and this is impossible with a tree since the decay is inside the tree trunk. Filling any hollow spots is not recommended.
Sometimes it is difficult to see all about a tree without being there. I think based on what I understand I would fertilize the tree and watch it over the years. And if the upper branches start to break off from the decay fungi I would then think about cabling the branches but I do not thing I would prune the branches back. The cabling would keep the branch from dropping and landing on something. The pruning would do not harm than good.
---------- FOLLOW-UP ----------
QUESTION: To answer your question: the limb that was cut was healthy. Did you mean to say that the pruning would DO MORE harm than good? We are not having limbs to fall. I have several great photos that I can show you. Is there a way to attach photos?
Answer
The trimming back of the limb can cause the entire limb to die. IF any limbs are pruned I would take them off back to the trunk or at least back a major large limb. Since the limb that was cut was healthy the tree sounds like it does not have much decay up into the trunk so I would just fertilize and leave it alone. You can attach a picture to a question--the attach "button" is near the bottom of the question screen.
