A cloud forest is a rare type of rain forest found on high mountains in the tropics.
Mist and fog cover the slopes either seasonally or year-round, and the plants that grow there draw moisture directly from those clouds, in a process called horizontal precipitation (precipitation is another word for rain). Horizontal rain can provide up to half the water a cloud forest needs to thrive, even during the dry season.
Cloud forests are found all around the world, including in Central America, southern Mexico, South America, southeast Asia, Africa, Madagascar, and certain islands in the South Pacific. All are packed with a wide variety of plant life -- so packed that there's big competition for growing space. Much of the vegetation consists of epiphytes, which are plants that grow on other plants but don't feed off of them. Instead, epiphytes (such as orchids, mosses, and lichens) draw nutrients from the air, the rain, and at times from organic debris around them.
These wet forests also provide shelter for a huge variety of animals, from insects and reptiles to many types of birds, monkeys, rodents, and even big cats. Some creatures are found only in cloud forests: In 2013, scientists announced the discovery of a mammal species called the olinguito, a tiny tree-dweller that lives in the cloud forests of Ecuador and Colombia.
Cloud forests are important due to their biodiversity, or wide range of plant and animal life. Their sensitive ecosystems make them useful for studying the effects of climate change, but that sensitivity also makes it hard for cloud forests to bounce back when disturbed.
In fact, cloud forests are disappearing at a slightly higher rate than regular rain forests, threatened by commercial logging, ecologically insensitive tourism, illegal development, and other factors. It will take a lot of effort by local communities and governments to preserve these special places.