generate questions: Heartwood (or duramen) is wood that as a result of a naturally occurring chemical transformation has become more resistant to decay. Heartwood formation occurs spontaneously (it is a genetically programmed process). Once heartwood formation is complete, the heartwood is dead. Some uncertainty still exists as to whether heartwood is truly dead, as it can still chemically react to decay organisms, but only once.
What's another word for "duramen"? {sep_token} What is heartwood naturally resistant to? {sep_token} How does heartwood formation occur due to its being genetically programmed? {sep_token} What adjective describes fully formed heartwood? {sep_token} Despite being considered dead, what can heartwood have one chemical reaction to?