Q: Why was the tree excited about the future?
A: It was ready to turn over a new leaf!
Explanation: “To turn over a new leaf” means to start anew, to start again, fresh. Someone who has had problems might turn over a new leaf and begin again (study more, learn something new, stop a bad habit, start a new good habit such as exercising, …).
A tree has many leaves (one leaf, two leaves). Do the leaves turn over? Not really but maybe before a storm.
This joke plays with the word leaf and makes me think about the future. What are your plans? Do you need to turn over a new leaf?