RE: Old apple tree questions
Prune out the dead branches first. Then remove anything that has diseased sections of wood. The best time for pruning is when the tree is dormant as it will have the greatest effect on the new growth but you can generally prune at any time. An exception is nut trees which "bleed" if pruned at the wrong time. After that you need to work on a long term plan to remove at the most 10% of the living tree each year and ending up with a wagon wheel when looking down from the top. As said before you want to remove rubbing branches and those that shade out others. Get out the chain saw.
Dan O.