It's hard—actually, impossible—to ignore the natural world in Hatchet. When a skunk sprays you in the face, can you ignore that?
From the moment the plane crashes into the lake, Brian becomes totally dependent on the natural world around him and on his ability to understand it and get what he needs from it. On the one hand, of course, this is a terrifying position to be in. Not only is Brian totally lost in an environment he's not equipped to deal with, but he soon learns that nature can be dangerously unpredictable—a place where a simple mistake can have dire, even fatal, consequences. There's no reset button in the woods. On the other hand, because of his absolute immersion in the wilderness, Brian ultimately discovers that the world is a far richer, more meaningful place than he had previously known. Life lesson officially learned.
In Hatchet, nature is presented as a powerful, destructive force that doesn't care who gets hurt as it goes about its business. Brian has to conquer nature in order to survive.
In Hatchet, nature is presented as a spiritual force. Brian, like the wolf and the bear, is part of nature, which he slowly comes to understand and appreciate.