In The Scarlet Letter, all the good stuff goes down in the woods. Secret trysts? Head to the wood. Major confessions? Head to the wood. Need to gather some medicine that actually works? Yep, head to the woods. Nature is almost like a character, personified as listening, commenting on, and interacting with the other characters. At the same time, it can be menacing. The Puritan community is like an island surrounded by nature, bordered on one side by a huge expanse of woods, home to Native Americans (the Wampanoag tribes); and on the other the big blue Atlantic Ocean.
In this story, nature is violent and deadly. Even if humans can survive in it, they have to be careful.
Nature represents everything the Puritan society tries to suppress or outlaw.