Question
What time of the year can I prune off the lower branches of a 30foot 10 year old tree?  I would like to take off all branches up to six feet from the ground.  Thanks

Answer
It's best to prune during times when the tree is dormant or has slowed down growth for the year. I would recommend late fall or winter. However, in your situation, the tree won't be seriously harmed if you were to prune it now.

I would recommend that you don't prune so that the crown is less than half the height of the tree (in this case, don't prune higher than 15').

You don't need to coat the knots, but when you prune cut the branches at the branch collar. This is a slight swelling at the tree trunk. Cut on the outside edge of this collar and the branch will grow over faster.

If you have larger branches that you have to saw, use two cuts, an upward cut for about 1/3 the branch diameter and then the downward cut. This will prevent the bark from being ripped.