birch bark vs birchbark canoe

birch bark and birchbark canoe both are nouns.

Word	Noun	Adjective	Verb	Adverb
birch bark	Yes	No	No	No
birchbark canoe	Yes	No	No	No

As nouns, birch bark and birchbark canoe are synonyms defined as:

birch bark and birchbark canoe: a canoe made with the bark of a birch tree

Other synonyms of birch bark include birchbark.

birch bark (noun)	birchbark canoe (noun)
a canoe made with the bark of a birch tree	a canoe made with the bark of a birch tree