At the climax of the story, when Goodman Brown believes he sees Faith consorting with the devil and subsequently loses his faith in God and humanity, Hawthorne personifies the devilish wilderness that surrounds Goodman Brown:
The whole forest was peopled with frightful sounds; the creaking of the trees, the howling of wild beasts, and the yell of Indians; while, sometimes the wind tolled like a distant church-bell, and sometimes gave a broad roar around the traveller, as if all Nature were laughing him to scorn.
The clearest example of personification comes at the end, when nature seems to be laughing at Goodman Brown's loss of faith, scorning his naivety for ever thinking that people were inherently good. This is fitting, since the story's motif of nature and wilderness associates nature with the evil that lurks at the heart of everything. Here, it seems that nature has always known the truth about people being evil, and because of that, nature is mocking Goodman Brown for coming to this knowledge so late and for feeling so distressed by it.
There's also some subtler, more complicated personification going on. At the beginning of the quote, it seems that Goodman Brown begins to hear the natural sounds of the forest as various unnatural sounds that would not actually come from trees. At first, the trees simply make a creaking sound, which is perfectly normal, but then their sound morphs into the howling of beasts, then into yelling Native Americans (which the story associates in a racist way with danger and evil). In this way, the forest grows progressively more human and sinister over the course of the quote, until the very end when it roars at him in a threatening way and then mocks his loss of faith.
When the forest becomes human through personification, it underscores a key thematic point of the story: that human beings are not separate from nature, and that since nature is inherently sinister and evil, human beings are, too.
