A tropical cloud forest is a type of mountain forest perpetually bathed in mist and low-lying clouds. These ecosystems are found in tropical regions where terrain forces warm, moist air to rise and cool, resulting in near-constant condensation at the canopy level. The persistent moisture and unique atmospheric conditions create an environment fundamentally different from other forest types.
Defining Characteristics and Climate
The existence of a tropical cloud forest is a direct result of orographic lift. As moisture-laden air currents from a nearby ocean encounter a mountain range, they are forced upwards. This ascent causes the air to expand and cool, leading to the condensation of water vapor into the dense cloud layer that defines the forest.
This constant cloud immersion creates a climate that is cooler and more humid than lowland tropical rainforests, with mean temperatures between 8 and 20 degrees Celsius. Cloud forests capture a significant amount of moisture directly from fog as it condenses on vegetation, a phenomenon known as fog drip. This constant dampness and reduced sunlight lower evapotranspiration rates, keeping the forest moist. The soil is acidic and rich in organic matter due to slow decomposition in the cool, wet conditions.
Global Distribution
Tropical cloud forests are rare, accounting for about 1% of the world’s total woodland. Their distribution is tied to mountainous regions within tropical and subtropical latitudes, generally between 23°N and 23°S. These forests are found on continents with suitable mountain ranges and climates, with major concentrations along the Andes Mountains, the highlands of Central America, and ranges across Africa, Southeast Asia, and the Caribbean.
Specific examples include Costa Rica’s well-known Monteverde Cloud Forest Reserve, with other significant forests in countries like Colombia, Ecuador, and Mexico. In Africa, they are found in places like Cameroon’s Gotel Mountains and on Mount Kilimanjaro. Southeast Asia’s cloud forests are located in Malaysia, Indonesia, and the Philippines, often on steep island mountains.
Unique Biodiversity
The constant moisture and cool temperatures of cloud forests foster a high level of biodiversity, particularly in adapted plant life. A primary feature is the abundance of epiphytes—plants that grow on other plants without being parasitic. Tree trunks and branches are often covered in thick blankets of mosses, lichens, and ferns. Orchids and bromeliads are also very diverse, with some forests hosting hundreds of different orchid species.
This dense vegetation provides a complex habitat for many animals, and numerous species are endemic, meaning they exist nowhere else on Earth. These forests are home to birds like the resplendent quetzal in Central America and numerous species of hummingbirds. Mammals such as the spectacled bear, South America’s only native bear, and mountain gorillas inhabit these high-altitude environments. The constant wetness also supports a variety of amphibians and insects specialized for this environment.
Ecological Significance and Conservation Concerns
Tropical cloud forests play a large role in regional water cycles. Their dense vegetation is efficient at capturing moisture from the clouds, allowing the forest to act as a natural “water tower.” It intercepts atmospheric water, stores it, and then slowly releases it into streams and rivers. This process ensures a consistent supply of clean water for downstream communities and ecosystems.
This function is under threat from human activity and climate change. Deforestation for agriculture, such as coffee or tea plantations, and cattle grazing is a primary pressure, leading to forest fragmentation. Climate change is another threat, as rising temperatures can cause the cloud base to lift to higher altitudes. If the clouds rise above the forest, the ecosystem loses its defining source of moisture, leading to drying conditions that harm its specialized flora and fauna.