The Eastern Arc is a chain of ancient mountains covered by rainforests and grasslands in Tanzania and Kenya.

Scientists believe that the forest has survived on the Eastern Arc Mountains for over 30 million years, and were once connected to the forests of the Congo Basin and West Africa.

Neighbouring mountains are much younger, for example Kilimanjaro is estimated to be about 1-2
million years old.

North/South Pare

West/East Usambara









Mwanga and Same

Lushoto, Korogwe, Muheza, Mkinga



Morogoro and Mvomero


Mpwapwa and Kilosa


Kilombero, Kilolo and Mufindi


Sanje Mangabey. An endemic
primate species discovered in
1979 in the Udzungwa Mountains

Many thousands of species of plants and animals are found in these forests and nowhere else on earth. This includes at least 100 species of birds, mammals, amphibians and reptiles; at least 500 plants and huge numbers of smaller creatures including butterflies and millipedes.

Many of these species are threatened with extinction.

The Eastern Arc is recognised internationally as an area with an exceptional concentration of species that occur nowhere else on earth.

The Eastern Arc supplies many resources and environmental services for the people of Tanzania. The total economic value of these resources has been estimated as at least $620 million.

Agriculture, industry and domestic users depend on the Eastern Arc for their water supply.

The Eastern Arc Mountains are the catchment areas for many of the important rivers of eastern Tanzania. The Ruvu River that supplies water to Morogoro, Coast and Dar es Salaam flows from the Uluguru Mountains; the Sigi river that supplies water to Tanga flows from the East Usambara Mountains.

Morogoro and Iringa receive most of their water from the Eastern Arc Mountains. The Wami, Kilombero, Little Ruaha and Pangani Rivers also flow from different ranges within the Eastern Arc Mountains and have enormous benefits for rural people and agricultural schemes in the lowlands. At least 25% of Tanzanians depend on the Eastern Arc Mountains for their water supply, and without this the economic future of the country would be in doubt.

Hydroelectric power using water from the Eastern Arc Forests contributes more than 50% of the electricity in Tanzania.

This power is essential to economic growth and development of the country. A reliable source of water is crucial to avoid serious power blackouts and shortages, with the major inevitable economic consequences.

The cool and reliable climate in the Eastern Arc allows the cultivation of many food and cash crops, which feed local populations and are exported to towns and cities.

Fruits and vegetables exported to Dar es Salaam and other large cities include bananas, apples, pears, peaches, plums, cabbages, potatoes, peas, and other specialist items such as leeks, celery, parsley and strawberries.

Food grown in the Eastern Arc and exported to towns makes a major contribution to feeding the people of Tanzania and reducing poverty. Due to fertile soils and sufficient rainfall the Eastern Arc Mountains area is famous for large scale farming of Cash Crops, e.g. Coffee, Tea and Sugarcane estates (Kilombero and Mtibwa Sugar Estates).

The forests and mountains of the Eastern Arc provide an attraction to visiting tourists.

Current tourist locations include the South Pare Mountains, Udzungwa Mountains National Park, Amani Nature Reserve in the East Usambaras, Lushoto in the West Usambaras and the area above Morogoro in the Uluguru Mountains.

The Eastern Arc is increasingly becoming popular with tourists particularly those with specialist interests in birds and wildlife. The area also offers an unparalleled wilderness experience for the more adventurous visitors.

Agriculture clearly marking the forest boundary.

Estimates suggest that more than 70% of the original forest cover has been destroyed and only about 5,400 sq km of forest remain on the mountains. Most of the forest has been lost in the past 100 years due to conversion to farmland, unsustainable timber harvesting and uncontrolled fires.

Conserving these forest habitats is very important for the global community and for the people of Tanzania. Most of the remaining forests are within government forest reserves. These government forest reserves are poorly funded and have few staff, however they provide the mainstay for conservation in the area.

Since 1998 local people often supported by civil society organisations have been increasingly involved in the management of the Eastern Arc Forests. This reflects a change in forest management policy in Tanzania.