Arbor means tree, so this is a day dedicated to trees, and to their natural beauty and to their preservation.
7 seconds sound clip from the It's Arbor Day, Charlie Brown movie soundboard.
You can hear this line at 00:04:58.724 in the DVD version of the movie.
Quote context
[...]
- Isn't springtime when a young man's fancy? How's your fancy, Linus?
- The first Arbor Day was April 10th, 1872, in Nebraska.
- The main idea of Arbor Day is that of conservation.
- Oh, Linus, you read so poetically.
- Linus, this gives me a wonderful idea.
- Then you can ask me to a movie and we can sit together.
- We can sip a drink from the same cup, a loving cup.
- You know what I don't understand, Chuck? I don't understand love.
[...]