How does the post card entry help set the tone for the following chapters

This sets the tone of Chris's personality. He is friendly but transient. He is just as comfortable leaving people as he is meeting them. Chris writes about his journey into the wild with little regard for the danger and hardships that wait for him. The second is an excerpt from Jack London, one of Chris's favorite authors. This one sets tone and context for the harsh perils of the wild that Chris never really understood.