National Tree Day is observed in Australia every last Sunday of July. Initiated by Planet Ark, an Australian non-profit environmental organization founded in 1992, the event has been celebrated annually since 1996. It invites individuals, families, schools, councils, and organizations to participate in tree planting activities across more than 4,000 sites. Since its inception, National Tree Day has seen the planting of 21 million trees and plants, with over 3 million participants involved in these ecological efforts. The organization also encourages sharing stories and photographs related to the event, which can be found on their dedicated website.