The world's largest rainforests
By Rhett A. Butler
July 11, 2020
Rainforests are found on all the world's continents except Antarctica. This article focuses specifically on the world's tropical rainforests.
The following charts show the extent of primary forest cover and tree cover in the tropics for the world's five largest blocks of rainforest: Amazon, Congo, Australiasia, Sundaland, and Indo-Burma.
The Amazon Rainforest
The Amazon is the world's largest rainforest. The Amazon rainforest, which includes parts of nine countries and covers nearly 40% of South America, accounts for just over half the primary forests found across the tropics.
In numeric terms, about 6.29 million square kilometers (629 million hectares) of the Amazon is forested, of which nearly 84 percent — 5.26 million sq km — is classified as primary forest. For comparison, the land mass of the United States is 9.15 million sq km, while Australia is 7.63 million sq km.
The Amazon rainforest has more than three times as much primary forest as the world's next largest rainforest, that of the Congo Basin. The Amazon rainforest accounts for just over a third of tree cover across the tropics.
The scale of the Amazon extends beyond its forest cover. The Amazon Basin has the world's largest river. While there is some debate over the world's longest river, there is no doubt that the Amazon River is the largest river: it carries more than five times the volume of the Congo or twelve times that of the Mississippi.
The Amazon rainforest also has the biggest population of indigenous forest peoples, including the greatest diversity of tribes and largest number of groups living in voluntary isolation. These groups are sometimes called "uncontacted tribes".
The Amazon rainforest has the highest biodiversity of any ecosystem, including more species of plants, birds, mammals, reptiles, amphibians, freshwater fish, and insects than any other place.
The Congo rainforest
The second largest block of tropical rainforest is found in the Congo Basin in Central Africa. About 2.87 million sq km of the basin is forested, of which 1.68 million is considered primary forest, as of 2020. That makes the Congo rainforest nearly the size of India's land mass.
Politically, the majority of the Congo rainforest lies within the Democratic Republic of the Congo (DRC), Gabon, Republic of the Congo, Cameroon, Central African Republic, and Equatorial Guinea. About 60% of the region's primary forest is in DRC.
Deforestation in the Congo Basin is currently trending higher. Nearly all primary forest loss in the Congo is occurring in DRC.
The Australiasian rainforest includes tropical forests on the island of New Guinea and northeastern Australia as well as scattered islands that were connected as a single land mass when sea levels dropped during that last ice age.
Virtually all this region’s primary tropical rainforest is on the island of New Guinea, which is roughly split between Indonesia and Papua New Guinea.
New Guinea is the most linguistically diverse island on the planet with some 800 languages. There are believed to be a few uncontacted groups in remote parts of New Guinea.
Sundaland includes the islands of Borneo, Sumatra, and Java, among others as well as Peninsular Malaysia. Most of the region’s remaining forest is on the island of Borneo, which is divided politically between Indonesia, Malaysia, and Brunei.
Sundaland lost the world’s largest share of primary forest cover between 2002 and 2019. Borneo lost 15% of such forests, while Sumatra lost 25%.
The Indo-Burma region includes a mix of tropical forest types. Historical large-scale forest loss due to human population pressure means that surviving forests in this region are more fragmented than other regions mentioned so far. Most of the region’s tree cover consists of plantations, crops, and secondary forests.
The largest extent of primary forests in this region are in Myanmar, which has about one-third of the total area.
Indo-Burma lost about 8% of its primary forests and 12% of its tree cover since 2001. Cambodia accounted for more than a third of the region’s primary forest loss during this period.
For world's rainforests day 2020, we published The world’s great rainforests.