Swamp White Oak

[Lorenzo]

About ten years ago I planted what was labeled as a "Swamp White Oak"

It has grown to a very nice thick hearty tree with big leaves. This tree holds on to it's leaves all winter and not until spring when the new buds push off the dead leaves will they fall.
Now that you know a little about the type of tree my question is what is the proper way to trim this type of tree and when is the best time Fall or Spring?.

It has branches within 2' of the ground and I am considering triming it so I can mow under it.  Will I harm it by cutting of some of it's lower branches?

[beenthere]

I wouldn't venture an answer to that without seeing a pic of the tree.

A guess, if it has grown well in the ten years, that trimming off lower branches will be ok, and good. Do so before the buds break or before April 1 (rule of thumb).

[Jeff]

Oaks should only be pruned when they are dormant.

[Texas Ranger]

Another rule of thumb is to prune leaving one half of the crown, may be a little close in your area.  Jeff is correct, prune when dormant.  There is also debate about using would spray.  Texas A&M put out a pamphlet that spraying live oak stubs reduced rot, I extend that to oaks in general and have anecdotal evidence of the wisdom of spraying. 

By the way,dormancy is just now breaking in the south, you should be good, if the snow isn't too deep, up nawth.

[Phorester]

Prune at most only about 25% of the crown in any one year.  Taking off any more than that will stress the tree.  You can take off more branches in succeeding years if you need to take off more of the crown, but never more than 25% in any one year.

But as Texas Ranger says, never more than 50% of the total crown.