lightwood vs blackwood tree

lightwood and blackwood tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
lightwood	Yes	No	No	No
blackwood tree	Yes	No	No	No

As nouns, blackwood tree is a hypernym of lightwood; that is, blackwood tree is a word with a broader meaning than lightwood:

lightwood: tall Australian acacia yielding highly valued black timber
blackwood tree: any of several hardwood trees yielding very dark-colored wood

Other hypernyms of lightwood include blackwood.

lightwood (noun)	blackwood tree (noun)
tall Australian acacia yielding highly valued black timber	any of several hardwood trees yielding very dark-colored wood