Importance of the plant sealing off the wound?

Tree wounds are common and the causes include: broken branches; impacts, abrasions and scrapes; animal damage; insect attack; fire; etc. Wounds usually break the bark and damage the food and water conducting tissues. Wounds also expose the inside of the tree to organisms, primarily bacteria and fungi that may infect and cause discoloration and decay of the wood. Decay can result in structurally weakened tree stems and can shorten the life of a tree. Decay cannot be cured. However, proper tree care can limit the progress of decay in an injured tree. This fact sheet discusses tree responses to wounding and what can be done after wounding to keep the tree healthy.