wood vs plant material

wood and plant material both are nouns.

Word	Noun	Adjective	Verb	Adverb
wood	Yes	No	No	No
plant material	Yes	No	No	No

As nouns, plant material is a hypernym of wood; that is, plant material is a word with a broader meaning than wood:

Other hypernyms of wood include plant substance.

wood (noun)	plant material (noun)
any wind instrument other than the brass instruments	material derived from plants
a golf club with a long shaft used to hit long shots; originally made with a wooden head
the trees and other plants in a large densely wooded area
the hard fibrous lignified substance under the bark of trees