In trees,
heart rot is a fungal disease that causes the decay of wood at the center of the
trunk and
branches. Fungi enter the tree through wounds in the bark and decay the heartwood. The diseased heartwood softens resulting in trees being structurally weaker and prone to breakage. Heart rot is a major factor in the economics of logging and the natural growth dynamic of many older forests. Heart rot is prevalent throughout the world affecting all
hardwood trees and can be very difficult to prevent. A good indication of heart rot is the presence of
mushrooms or fungus
conks on the tree.