Discuss that squirrels gather nuts as they fall and store them for the winter.
Explain that nuts are the tree's seeds. Sometimes squirrels will bury nuts and forget to eat them, those nuts will sprout from the ground and a new tree will grow.
Sing the song:
(to the tune of "You Are My Sunshine")
I am a squirrel, a little squirrel.
I gather nuts when they fall from trees.
In the winter, you'll never find me
Cause I'm warm in my home on cold days like these.