Being in the thick of a forest is an example of being amidst a forest.
Origin of amidstamid + Middle English adv. genitive -s + unhistoric -t
Origin of amidstMiddle English amiddes amidde ; see amid . -es adverbial suffix ; see -s 3.
As with other words with excrescent suffix -st, amidst is generally considered synonymous with simpler amid, and amid is preferred by style guides on both sides of the Atlantic.
Further, amidst/amid are similar in meaning to – but distinct from – amongst/among. Amid(st) denotes that something is "in the midst of", "surrounded by" other things, and is used when the idea of separate things is not prominent. Among(st) denotes that something is mingling with other separable things ("blessed art thou among women").