We have a large beautiful maple tree in the center of our back yard. Several years ago the local power came through and cut one of the large limbs close to the power line clear to the tree itself. Since then in the years since, the spot has rotted and is not receding into the tree mostly because of it holding water from rain. We have had several suggestions on what we should do. One is to drill a hole farther down in the tree so the water will run out and not remain in the rotted area to stop it from continuing to rot. The 2nd was to let it dry and then fill it completely with concrete. The people who did the cut say not to worry about it. We have recently built a deck and sliding doors off the house and do not want to lose the shade or the beauty of the tree. What is the best way to keep this tree? We do not want to lose it at any cost. Thank you

We always used tar to seal and allow it to heal and not hold water

Thank you for the quick response, but the problem is the are had already receded several inches so tarring it would do little to help it now. Thank you, anyway

OK here's the deal. I've done quite a few repairs like this on a tree.

1. Clean out all of the rotton wood and insects.
2. Only if you have to use a mild spray insecticide.
3. Let dry thoroughly
4. Use either or both tree wound dressing or spray undercoating to create a light film everywhere. Let dry thouroughly.

Don't use concrete, but rather use Rockite. You can apply in sections. The first objective is to allow water to drain and or sit inside the tree. This stuff is an expansion cement and thus it expands when it cures. True Value hardware carries the product. When you apply it, TRY to make the patch about 1/4" inside the tree shape. If you have to use forms, do so. The tree the will want to grow around the patch.

Unfortunately, you now have a wounded tree and that means inspections and continuous repairs which are not extensive.

Once the cement sets, again coat with undercoating or tree wound dressing.

It basically means keeping water out of the cracks which could freeze in the winter and check to make sure the bark around the wound is sound.

The success of the repair depends on keeping the water out and providing an opportunity for the tree to heal itself.