Question
QUESTION: I have a very old (possibly 100 years old) and very large Maple tree which stands just outside my Vermont home. The core of this tree has a hole which faces skyward. We've had a lot of rain and I'm afraid that like my next door neighbor's tree, my tree may also surcome to rot and split apart. Can I pour tar into the hole and will that solve the water soaking problem? I've tried to get a tree guy here but no one seems available except for huge sums of money which I do not have. Thanks. Joanne

ANSWER: tar would damage the trees cells. The tree is more than likely hollow. Fungi get into the woody part of the tree and decay the wood. This does not bother the overall health of the tree but as you say may weaken the trunk which may split limbs off during high winds. The hole will allow water in get in the tree. The old method was to add cement in the hollow but this was found to cause more damage than it did good. The hollow is like a tooth with decay to stop the decay you would have to "drill" out the old decaying wood but this is impossible in a tree. You can seal the opening by adding foam insulation. This foam is squirted in the hole and it expands to fill the hole and some of the hollow. Over time the tree will grow and this will become loose. So it is not a cure just a way to keep some of the water out. The best thing to do is keep the tree healthy by fertilizing the tree with 10-10-10 fertilizer at the rate of 1 lb per inch of trunk diameter scattered around the tree and watered in good.

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QUESTION: Follow up question. The trunk of the aforementioned Old Maple Tree with the Hollow is approx 80" in circumference.
The tree itself, which towers over my house is about four stories tall. My question, can it be "saved" or is this an accident waiting to happen? Thanks again. Joanne in Vermont

Answer
As long as the foliage looks full and healthy the tree is in good shape as far a living. It has been in this condition for quite some time to have this large a hollow trunk and has with stood many wind storms. I would say the tree is strong. If the foliage and the crown start to give way then you might consider replacing it. Usually the first thing that will break would be a large limb and this would be hollow. If this happens you will be able to determine how high up the tree trunk the hollow extends and the risk of falling maybe higher. Right now sounds like it is ok just keep it healthy.