In fact, the sixteenth chapter is titled “In Which Trouble Begins.” Sam refers here to his interactions with people in the nearby town. When he walks into a store wearing his deerskin clothing, a young man (“Mr. Jacket”) calls him “Daniel Boone” and asks about where he lives and what he does. It feels nice, talking to another person again. And yet, if too many people know about Sam, they may pose a threat to his lifestyle. He doesn’t want anyone coming up to his mountain home and interfering with his days. He doesn’t want any authorities insisting that he go back home to his family in New York City.

The seventeenth chapter is titled “In Which I Pile Up Wood and Go on with Winter.” Here, Sam continues the story that he used to begin the book. He survives the snowfall by keeping a fire going with the wood he collects. Frightful the falcon hunts for food for him, in the snow. Sam eats Bando’s jam and acorn and hickory pancakes. Even though the weather can cause trouble in finding enough food and shelter and warmth, Sam has successfully learned how to deal with these issues.

The eighteenth chapter is titled “In Which I Learn About Birds and People.” Winter continues. Sam describes some of the animals he sees, especially the birds. And it’s time for Christmas. Both Bando and Sam’s father come up the mountain to visit with him. Bando brings along three local newspaper articles that claim that a boy is living in the Catskills on his own, stealing deer from hunters. This is exactly the kind of publicity that Sam doesn’t want or need. Now more people may try to find him. This kind of “trouble” can only escalate. And, as we see in the rest of the book, it does.

The chapters in this book aren't actually numbered, so I hope I have selected the correct ones you are refering to. The biggest immediate trouble that Sam experiences is of course the approaching blizzard. Sam has to work very hard to create a wood supply that will keep him warm throughout the entire winter. However, when he has done this, Sam actually finds that he loves winter and greatly enjoys the close communion that he has with animals.

It is when Bando arrives that an even bigger problem rears its ugly head. Bando shows Sam some newspaper articles about him, calling him a "Wild Boy" and stoking the myth of his existence. This of course represents an intrusion of the world of men into the world of nature that Sam has inhabited, and of course, after winter ends, Sam knows that people will be searching for him and will try to invade his tranquil and peaceful existence. This is the big example of "trouble" that is alluded to in these chapters.