Sam's story has lessons about several kinds of survival. Some of them involve developing the skills to live alone in a challenging physical environment, while others are concerned with the social and emotional aspects of human interaction.
Sam is an urban kid who wants to live in nature but also to connect with a family legacy. He has to rely on people such as the librarian Miss Turner to find his ancestral land, and to distance himself from his family's doubts. Once on the land, he sees his place within the environment includes relating to other species, reciprocating as well as taking. This is seen especially with the falcon, and in mistakenly inviting and feeding wild animals. He figures out how to make shelter without building, adapting ancient techniques to shape the tree trunk into a home.
Continuing to develop relationships and skills, recognizing that initial familiarity is the first step rather than complete mastery, is the key to Sam's continued survival through his year. The lessons from his stay in the Catskills, the reader comes to believe, are lasting ones. Sam has likely developed an attitude toward learning as well as the necessary self-reliance to survive varied future challenges.