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.

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