It is a Friday in spring and your class is studying trees. But do you know why? It's Arbor Day, of course! Turn the pages of this book to find out: what North America looked like five hundred years ago, why trees are important in windy places, why some states do not celebrate Arbor Day on the same date. Each book in the Holiday Histories series describes one of America's holidays or special days. Explore the history of each day and learn the real reason why it is important. Discover what special meaning each day might have for you.