The National Festival of Trees, known as Nationale Boomfeestdag, is observed in the Netherlands every third Wednesday of March. This festival, established in 1957 by the National Committee of Tree Planting Day, primarily focuses on encouraging children to plant at least one tree. Its origins trace back to a 1954 United Nations resolution that emphasized the importance of trees and recommended member states to hold a special tree festival annually. The celebration takes place in schools across all Dutch municipalities, although some regions may observe it around September 21. Each year, the organizing committee selects a special theme, while municipalities and schools are also free to create their own themes for the event.