Final answer:
The boy's second request was a boat, and the tree provided its wood to make the boat, representing selfless love and sacrifice.
Step-by-step explanation:
The second thing the boy requested from the tree was a boat. In response, the tree offered itself, allowing the boy to cut it down to make a boat. This act of kindness is meant to symbolize the tree's unconditional love and sacrifice for the boy's happiness, which is a central theme of the story.