Question
Is it safe to prune a live oak tree in Houston during the summer?  Or do I need to wait until winter to avoid too much stress?

Answer
While deciduous trees can be pruned anytime during the year, the best time to prune is late winter or early spring before the trees leaf out. To prevent the spread of oak wilt, avoid pruning oaks from April 1 to July 1. Pruning oaks during this period may attract sap beetles carrying the oak wilt fungus to the pruning cuts and transmit the disease to healthy trees. An excellent time to prune oaks is February and March.