forest vs vegetation

forest and vegetation both are nouns.

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

Other hypernyms of forest include botany, flora.

forest (noun)	vegetation (noun)
the trees and other plants in a large densely wooded area	all the plant life in a particular region or period
land that is covered with trees and shrubs	the process of growth in plants
	an abnormal growth or excrescence (especially a warty excrescence on the valves of the heart)
	inactivity that is passive and monotonous, comparable to the inactivity of plant life

forest (verb)	vegetation (verb)
establish a forest on previously unforested land