Where do you live?

If in Southeastern US, in zone 8 or warmer, I'd say in fall or winter, however, I read that to prevent the spread of oak wilt, pruning should NOT be done in spring (they defined 'spring' as February 1 through June 30) when the insects that vector this disease are most active.

If you must prune this time, they recommend painting the cuts immediately.

Here is a link that might be useful: Pruning guidelines

This post was edited by dave_in_nova on Fri, Jan 9, 15 at 8:54

Here's another interesting article.

Here is a link that might be useful: Pruning live oaks

If you're in Texas, then the oak wilt issue is definitely a concern, and I'd avoid pruning in spring (through June). In many other parts of the southeast (such as Florida), oak wilt has never been documented. Here I consider winter up until the first flush of spring growth to be a good time, but live oaks don't seem to be super-sensitive about the timing.

Not Spring

Actually the university of Texas says late July when it dry

It may be dry in Texas in late July, but OP doesn't say where said live oak lives.

If we have a tropical storm in summer, we can get lots of rain and live oaks start to grow again. I'm not sure you want to prune a lot in late summer as new growth would be more vulnerable to frosts.

It would help to know where OP lives.

Sorry all. I am in coastal Mississipi. Given your input I,m gonna say now would be ideal? Also, should I paint the pruned area and with what? Thank you all.

Dave, Jon put the location on the My Page page where his name is. I have forgotten about that many times. Not to be a smart ass, but many peeps will put their location there, but lots just put their country location there also. I guess some peeps aren't sure what their gardening zone even means if they are a newbie, or they would put it where it says zone. I hope you get my meaning Dave. Again no smart-ass isms intended, I figured you didn't know about that. Poaky1

Jon, while tree wound dressings, paints, etc. have been largely discredited since about 1980, yours is the one situation where their use can still be justified. At least up here in my area, the picnic beetle-that little guy that ends up in your beer on a warm summer evening-is the main vector of the oak wilt fungus. This insect is attracted to yeasty, fungusy smells. By coating the pruning wounds with the tree paint, the transmission of fungal spores or bits of mycellia is largely prevented. So for this reason, and this reason alone, a coat of asphaltic tree paint is indeed recommended.

+oM

To my knowledge, oak wilt has never been reported in coastal Mississippi (although it has been found in a couple of counties on that state's northern border).