Howdy folks,
In regards to this exchange:
In your opinion, what is the best time of year to trim oak trees?



in the winter

I would add, the reason being is that like all trees there is less
stress , pruning while the tree is dormant ( and of course you can see
what you are doing ). With Oaks to protect against Oak wilt spread,
keep a bucket of water/ bleach solution to disinfect your shears
between cuts and paint the cuts with pruning sealer ( a spray can
works for small cuts, a brush for big cuts ). In addition, get a book
( I think Sperry's Texas Gardening will do ) or pull up a web site
with tree pruning illustrations to show the proper location of the
location of the cuts, it's important and you don't want a careless
job.
take care,
Steve Coyle
www.austingardencenter.com