A tropical forest is any forest growing in the warm, frost-free belt near the equator, roughly between 23°N and 23°S latitude. These forests receive at least 100 cm (about 40 inches) of rain per year, maintain average temperatures between 20°C and 30°C year-round, and support more biodiversity than any other land environment on Earth.
The term covers a wide range of forest types, from the dense, dripping rainforests most people picture to drier, more open woodlands that lose their leaves for part of the year. What unites them is warmth, moisture, and an extraordinary concentration of life.
Where Tropical Forests Grow
The densest tropical forests, the humid rainforests, cluster closest to the equator, between 0° and 10° latitude north and south. Here, rainfall is heavy and spread fairly evenly across the year, often reaching 200 to 450 cm annually. Tropical dry forests extend farther from the equator, between about 10° and 23° latitude, where rainfall is more seasonal and a distinct dry period can last four to seven months.
The largest blocks of tropical forest sit in three major regions: the Amazon Basin in South America, the Congo Basin in Central Africa, and the islands and peninsulas of Southeast Asia. Smaller patches stretch across Central America, coastal West Africa, Madagascar, and parts of South Asia and northern Australia.
Climate and Weather Patterns
One defining feature of tropical forests is how little the temperature changes from month to month. In humid tropical forests, the average hovers around 26–27°C all year, with daily swings of only about 5°C. That consistency matters: it means biological processes like growth and decomposition never slow down for a cold season, so the whole ecosystem runs at high speed year-round.
Tropical forests also generate a surprising amount of their own rainfall. Trees pull water from the soil and release it through their leaves, a process called evapotranspiration. In the Amazon, forests release roughly 1,100 liters of water per square meter each year, and about a third of that moisture falls again as rain over the region. This self-watering cycle means that large-scale forest loss doesn’t just remove trees; it can reduce rainfall hundreds of kilometers downwind.
Types of Tropical Forest
Not all tropical forests look alike. The main categories differ primarily in how much rain they receive and when it falls.
- Tropical rainforest: The wettest type, receiving 200 cm or more of rain per year with no prolonged dry season. Canopy trees can reach 50 meters or taller, and the understory stays dim and humid.
- Tropical dry forest: Receives 100–200 cm of rain annually but endures a dry season of several months. Many trees shed their leaves during the dry period, letting sunlight reach the forest floor and creating a more open, seasonal landscape.
- Tropical montane forest (cloud forest): Found at higher elevations, typically above 1,000 meters. Cooler temperatures and persistent fog support thick carpets of mosses and ferns, and trees tend to be shorter and gnarled.
- Tropical forested wetland: Forests that are flooded seasonally or permanently, such as the várzea and igapó forests along Amazonian rivers or coastal mangrove stands.
Biodiversity Hotspots
Tropical forests cover roughly 6–7% of Earth’s land surface yet contain a vastly outsized share of its species. A 2022 study found that tropical forests harbor 62% of all terrestrial vertebrate species, more than double the number in any other land biome. That figure includes mammals, birds, reptiles, and amphibians. When insects, fungi, and plants are added, the proportion climbs even higher, though exact numbers are harder to pin down because millions of tropical species remain undescribed.
This concentration of life results from stable, warm conditions over millions of years. Species have had time to specialize in narrow niches: a particular layer of the canopy, a single type of fruit, or a symbiosis with one pollinator. A single hectare of Amazonian rainforest can contain 300 or more tree species, compared to perhaps 20 in a temperate deciduous forest of the same size.
How Plants Adapt to the Forest
Life in a tropical forest presents two overlapping challenges: intense competition for sunlight and surprisingly poor soil. Plants have evolved creative solutions to both.
Because tropical soils (often a type called oxisols) are heavily weathered and naturally infertile, trees can’t invest in deep root systems that mine nutrients from bedrock. Instead, many large trees develop buttress roots: wide, wing-like extensions that fan out from the base of the trunk. These structures stabilize the tree in shallow soil and help channel surface nutrients toward the root system.
Higher up, epiphytes solve the light problem by skipping the ground entirely. Orchids, bromeliads, and ferns grow on the branches and trunks of larger trees, drawing moisture and nutrients from the air and rain rather than from soil. They aren’t parasites; they simply use the host tree as a platform to reach sunlight. In some rainforests, epiphytes account for a quarter or more of all plant species. Woody vines called lianas take a different approach, rooting in the ground but climbing host trees to reach the canopy, sometimes spanning gaps between treetops and forming aerial highways used by monkeys and other arboreal animals.
Soil and Nutrient Recycling
The lush appearance of a tropical forest is misleading if you assume the soil underneath is rich. Oxisols and similar tropical soils are dominated by quartz, clay minerals, and iron oxides, a combination that holds very few plant-available nutrients. Most of the ecosystem’s nutrients are locked in living biomass, not in the ground.
What keeps the system running is speed. Fallen leaves, dead insects, and animal waste decompose in weeks rather than the months or years typical in cooler forests. Fungi and bacteria break down organic matter rapidly in the warm, humid conditions, and a dense mat of fine roots near the surface absorbs released nutrients almost immediately. This tight recycling loop means that when tropical forest is cleared for farming, the soil’s fertility can drop sharply within a few growing seasons once the recycling machinery is gone.
Carbon Storage and Climate
Tropical forests are the largest living carbon warehouse on land. A mature tropical moist forest stores about 130 tons of carbon per hectare in above-ground biomass alone, with additional carbon in roots and soil. Actively growing tropical forest absorbs roughly 11 tons of CO₂ per hectare per year, which works out to about 18 kg of CO₂ per tree annually at typical tree densities of around 600 trees per hectare.
That storage capacity makes deforestation a significant source of greenhouse gas emissions. When trees are burned or left to rot, the carbon they accumulated over decades returns to the atmosphere quickly. In 2024, 6.7 million hectares of tropical primary forest were lost globally, largely driven by fire. That’s an area roughly the size of Sri Lanka disappearing in a single year, releasing stored carbon and eliminating future absorption capacity at the same time.
Threats to Tropical Forests
The biggest driver of tropical forest loss is land conversion for agriculture, particularly cattle ranching, soy cultivation, and palm oil plantations. Logging, both legal and illegal, opens access roads that lead to further clearing. Mining, urban expansion, and infrastructure projects add additional pressure.
Fire has become an increasingly destructive force. Many tropical forests are not adapted to burn; their interiors are normally too damp for fire to spread. But when forests are fragmented and edges dry out, or when drought events intensify, fire can sweep through areas that historically never burned. The 2024 loss figures highlight fire as a major and growing component of tropical deforestation.
The consequences extend beyond the tropics. Losing large forest blocks disrupts the evapotranspiration cycle that generates regional rainfall, potentially pushing remaining forest toward a drier, more fire-prone state. This feedback loop is a central concern in the Amazon, where researchers have warned that continued clearing could shift large areas from forest to savanna-like vegetation, with cascading effects on rainfall patterns across South America.