On March 21, the world celebrates the International Day of Forests. Forests come in all shapes and sizes! Trees with wide, flat leaves make up broadleaf forests. Forests surrounding the Ozark Mountains in the U.S. states of Oklahoma and Arkansas are broadleaf forests. Trees in coniferous forests don't have leaves at all—they have thin, narrow needles. The forests surrounding the mountains of central Honshu, Japan's biggest island, are coniferous forests. Tropical rain forests are hot, humid places usually found near the Equator. The world’s biggest rain forests surround the Amazon River in South America and the Congo River in Africa. Cloud forests are often covered in low-level clouds and fog. Cloud forests are often found in mountainous areas, such as the Western Ghats in India and the Coastal Range in the U.S. states of California and Oregon. Boreal forests are found in colder climates. In some regions, hardy evergreen trees can withstand snow and freezing temperatures almost year-round. Boreal forests are also called the taiga. The taiga extends across Northern Russia, Scandinavia, and the Arctic regions of Canada and the U.S. state of Alaska.