Question
Jim, I live in Westchester county, New York and have a 250 yr old oak tree and would like to know the times to prune live branches. I have a very large branch that goes down to the base of the tree with very little on it and also would like to know if it is a bad idea to remove it. Any info to keep this old tree healthy would be appreciated. Thanks, Tony

Answer
For oak trees, the recommended pruning time is November through March. In the summer months, pruning oak trees can attract small beetles that spread oak wilt fungus disease. If you don't prune your oak trees between April and October, you can prevent your oaks from getting this disease.

PROPER BRANCH PRUNING
To shorten a branch or twig, cut it back to a side branch or make the cut about 1/4 inch above the bud.


Always prune above a bud facing the outside of a plant to force the new branch to grow in that direction.
Figure 2. Pruning small branches

Pruning large branches  

To remove large branches, three or four cuts will be necessary to avoid tearing the bark. Make the first cut on the underside of the branch about 18 inches from the trunk. Undercut one-third to one-half way through the branch. Make the second cut an inch further out on the branch; cut until the branch breaks free.


Before making the final cut severing a branch from the main stem, identify the branch collar. The branch collar grows from the stem tissue around the base of the branch. Make pruning cuts so that only branch tissue (wood on the branch side of the collar) is removed. Be careful to prune just beyond the branch collar, but DON扵 leave a stub. If the branch collar is left intact after pruning, the wound will seal more effectively and stem tissue probably will not decay.




The third cut may be made by cutting down through the branch, severing it. If, during removal, there is a possibility of tearing the bark on the branch underside, make an undercut first and then saw through the branch.


Research has shown wound dressing is not normally needed on pruning cuts. However, if wounds need to be covered to prevent insect transmission of certain diseases such as oak wilt, use latex rather than oil-based paint. For cut larger than 5-6 incehs I would paint the wound with a wound dressing/paint. Check with your local nursery fro these.