Above: heartwood formation can be stopped by a deep wound.
Above: in a cutaway of an ash, a column of discolored and decayed wood is associated with a wound developing around a central column of decay caused by old, poorly healed branch stubs. (Note from webmaster - when the word healed is used here, what is meant is closed or sealed. JAK)
Above: radial view of decay in a wounded peach tree.
Page 22