English: Tree cankers (right) are caused by injuries to the bark that allow pathogens or insects in to infect the tree. Compared above is a healthy tree and segment (left) to a tree infected and containing a canker.
Tree cankers (right) are caused by injuries to the bark that allow pathogens or insects in to infect the tree. Compared above is a healthy tree and segment (left) to a tree infected and containing a canker.