Question
Hi Jim. I have 3 live oak trees that were planted approx: 5 years ago from a nursery when they were about 6 feet tall. They are now about 20-25 feet high. I have topped these trees twice now, about only 2-3 feet to get a better growth outward. I would like to bottom prune now and was wondering if there is anything I should know.Thank you

Answer
I am not sure what your desired outcome you want. Some folks want live oaks that the branches reach to or near the ground others want "regular tree" shape. Topping trees is never good for them and makes a bush rather than a tree IF they live. Trees will grow out in width and the width will depend on the tree species and age of the tree.

Saying all that yes you can prune the lower limbs but I would wait until the winter months or at least until the hardwood trees around have dropped their leaves. The tree is dormant then and there will be less bleeding that can attract insects. Cut the branches off to about 1/4 inch from the main trunk--this will heal over faster. Pruning now will cause sap flow that will attract insect like borers that will enter the tree. So wait until the Fall or later.