For example, a tree that has been struck by lightning or bumped with logging equipment may have an open wound that the tree is attempting to heal. In the healing process, the tree first forms callus tissue, then woundwood and eventually normal wood. Without adequate water throughout the tree, the restoring process may fail, and the tree will eventually die. Another case occurs when Southern pine beetles attack pine trees. This process is much more successful if the tree is actively growing because the quantity and force of the sap flow will be greater.
Droughts lessen the sap flow, and the result is often a red-topped pine tree.
Most other trees should endure this year's drought. Orderly and planned timber harvesting will maintain healthy and vigorously growing trees. D trees can then be salvaged by harvesting before they reach the final stage of D . . . But in reality, other factors are often more important. The ranking is called the job queue for that position.