Plant trees. As the date of Earth Day roughly coincides with U.S. Arbor Day, planting trees is a popular Earth Day activity. Trees helps to reduce greenhouse gas emissions, clean pollution, secure soil in place to prevent erosion, and provide homes for many birds, insects and other animals. There's almost no more important, long-lasting act you can do to celebrate Earth Day.
Pick a tree that you know can survive in your climate. It's best to find a species native to where you live. If you're unsure about what that might be, ask an employee at your local garden shop, or inside the garden department of a big-box store.
To ensure that the tree grows tall and strong, make sure you plant it correctly. Choose the correct planting spot to meet its needs, dig a properly-sized hole, and water the tree well to give it a good start.