family tree vs kinship group

family tree and kinship group both are nouns.

Word	Noun	Adjective	Verb	Adverb
family tree	Yes	No	No	No
kinship group	Yes	No	No	No

As nouns, kinship group is a hypernym of family tree; that is, kinship group is a word with a broader meaning than family tree:

Other hypernyms of family tree include clan, kin, kin group, kindred, tribe.

family tree (noun)	kinship group (noun)
successive generations of kin	group of people related by blood or marriage