The definition of amidst is being surrounded by something or having something going on all around you.(preposition)
Being in the thick of a forest is an example of being amidst a forest.
See amidst in Webster's New World College Dictionary
Origin: amid + ME adv. gen. -s + unhistoric -t
See amidst in American Heritage Dictionary 4
Origin: Middle English amiddes
Origin: : amidde; see amid
Origin: + -es, adverbial suffix; see -s3.