The Oregon white oak or Quercu garryana (sometimes referred to as the Gary oak) is a deciduous tree that can grow to a height of 90 feet and a width of more than 125 feet. The crown is rounded, and the limbs are crooked, giving it a rough or rugged appearance. The leaves turn brown and sometimes slightly red during the fall season. Oregon white oaks require pruning to remove diseased or damaged branches, to maintain a size that is appropriate for its space in your landscape and to keep it away from structures or roofs.
Cut off any damaged or diseased branches or limbs as soon as possible. Be sure to make a clean cut where the break has occurred so that proper healing can take place. You can do this pruning procedure at any time of the year.
Determine where to prune to maintain size or ensure safety by locating the branch collar (this is on the underside of the branch where it connects to the trunk) and the branch bark ridge (this is on the topside of the branch where it connects to the trunk). Make a clean cut right in front of the branch bark ridge and the branch collar. Do not leave a stub. Do not cut into the branch collar or the branch bark ridge. This must be maintained for the health of the tree. This pruning procedure can be done during early spring or late fall when the tree is still in a dormant state.
Make a visual inspection of your mature tree for deadwood and cross over branches as they should be removed. This pruning procedure is called thinning and is usually done by a professional. A certified arborist knows exactly what branches to cut to maintain the health and appearance of the tree.