Arbor Day is a nationally-celebrated observance that encourages tree planting and care. National Arbor Day was founded by J. Sterling Morton in 1872 and is celebrated on the last Friday in April, but many states observe Arbor Day on different dates according to their best tree-planting times. Click here for a map to find out when your state observes Arbor Day.

MORE: Read an editorial about trees from Arbor Day Foundation president and CEO John Rosenow