vegetation vs accumulation

vegetation and accumulation both are nouns.

Word	Noun	Adjective	Verb	Adverb
vegetation	Yes	No	No	No
accumulation	Yes	No	No	No

As nouns, accumulation is a hypernym of vegetation; that is, accumulation is a word with a broader meaning than vegetation:

Other hypernyms of vegetation include aggregation, assemblage, collection.

vegetation (noun)	accumulation (noun)
inactivity that is passive and monotonous, comparable to the inactivity of plant life	the act of accumulating
an abnormal growth or excrescence (especially a warty excrescence on the valves of the heart)	several things grouped together or considered as a whole
all the plant life in a particular region or period	(finance) profits that are not paid out as dividends but are added to the capital base of the corporation
the process of growth in plants	an increase by natural growth or addition