In Woodsong, there is no traditional antagonist. Instead, Gary Paulsen faces off against nature as he grows up in the north and later lives in an isolated home with his wife and family.
Paulsen sees both the beauty and the danger of nature throughout the book. He sees a deer torn apart by wolves, and as he watches them begin to eat her alive, he has a realization. The wolves—and by extension, the harshness of nature—are not necessarily bad. They just are what they are. He says that it would be wrong for him to expect them to be anything else.
When Paulsen decides to run the Iditarod, he tests himself and his team of dogs against nature. Though he is injured at times and occasionally strained to the point of hallucination, he still completes the race. He finds joy in nature, even though nature itself is the only thing that presents danger throughout the book—whether it's in the form of a hungry bear or in the form of an extremely low temperature.