Examine the leaves. If they are bronze and wilting, the tree may be affected by oak wilt, a fungal disease. It makes its way through oak trees with the help of borers, beetles and squirrels. If your tree is affected, you should remove it. There is no reliable treatment.
Look under the tree. Weeds choke the life out of live oak trees. Remove the alien grasses by hand, trying not to disturb the soil too much. Cover the area with 2 inches of mulch.
Prune during dormant season only. This reduces the spread of potential diseases like oak wilt. Cut off diseased, dead and weak limbs at the connection they share with healthy wood. Make the cuts just outside the branch collar, which is the swollen section at the joint. Bring a professional arborist in every five years to prune the tree, especially as it grows too large to handle on your own.
Use well-draining soil. Live oaks can suffer from root rot in coastal areas. Transplant small to medium oak trees if water pools around their trunks. Have large oaks professionally removed if they are suffering from root rot.