The Monteverde cloud forest of Costa Rica is also known as the fog forest. These are tropical or subtropical evergreen forests. They are popular for 100% humidity and heavy rainfall, which is due to the surrounding clouds and mist. This forest contains short and crooked trees, trunks of which are usually covered with a thick layer of mosses, climbing ferns, lichens and air plants (such as orchids). Certain plants like begonias, ferns and a few varieties of herbaceous plants attain a large size in the flat clear zones of the forest. The trees in this forest are called elfin as they are short in height.