Who is Stuart from A Year in the Maine Woods and what is their importance?

Stuart is Heinrich's nine-year-old son. Stuart lives mother because his parents are divorced, but he comes up to the cabin for frequent visits. Like his father, Stuart is interested in the natural world. He loves staying at the cabin and spending time with his father. Heinrich often worries about entertaining Stuart while he's visiting, but Stuart is happy to simply sit and enjoy the natural world and ask his father questions.