I remember reading this book almost 15 years ago so it has to be older than that. It's about a boy who I'm pretty sure is either hunchbacked or has some other physical deformity who moves with his family from the city to the forest, which is great for him because it means he can swing through the trees all day long. Whenever he gets a chance he secretly goes camping in the forest, travelling by going from branch to branch. One day he discovers what I think are a community of elves but might be something else living in the forest and becomes friends with them. However the forest isn't safe as there's evil snakes who can talk who stick to the ground and are a threat to the elves and to him, with a girl in his class eventually discovering his secret adventures. I'm pretty sure at one point the elves literally have a magical woven tapestry and talk about threads of destiny and that the book ends with the kids helping the elves escape the danger of the snakes by going on a cruise ship.