National Tree Day is an environmental event coordinated by Planet Ark, an Australian not-for-profit Environmental organisation. It is designed as a day to encourage the average Australians to care for the nature by planting trees. A special day for school—Schools Tree Day is also combined to raise the environmental awareness of children in a way that they find interesting. Every year about 200,000 students take part in the school tree day event.
National Tree Day is on July 29 while School Tree Day is on Friday July 27 this year. You can find more about the tree day information here.