The Batang Toru Ecosystem -
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The Batang Toru Ecosystem, also called “Harangan Tapanuli” in Batak language, ranges from hilly lowland tropical rain forest to rugged mossy submontane forest in the highlands. It stretches across three districts in Tapanuli, North Sumatera.


What is now left of this unique forest spans some 141,749 hectares, divided in two main blocks separated by the Sumatran rift valley. Most of the surrounding lowland areas have been opened up for agriculture and plantation development.

The communities surrounding the Batang Toru Ecosystem depend on this humid, tropical forest and the high levels of rainfall it produces as their main water source and buffer against flooding and erosion. This forest is part of the Barisan mountain range in Sumatra that is increasingly vital for the role it plays in storing carbon dioxide and mitigating the effects of climate change.

The Batang Toru Ecosystem is also the last habitat for the newly described, critically endangered Tapanuli Orangutan, the rarest great ape in the world. Tapirs, Sun Bears, Serow, Golden cats, and the critically endangered Sumatran tigers are also still found in these forests.


Most of the Batang Toru Ecosystem is currently allocated as protection forest. One inactive logging concession had a license to operate in part of this rugged forest, but there has been no legal logging since 2001. Illegal encroachment is still ongoing by immigrant settlers from Nias and illegal logging is occurring in some areas. Hunting for food and trade threatens the endangered wildlife. A massive planned hydrodam and an expanding open pit gold mining operation are current major threats to the Batang Toru Ecosystem.


YELPanEco has been working towards protection of the Batang Toru Ecosystem since 2006. North Sumatra’s governor and the local Tapanuli Governments have agreed that most of this forest should be protected, and currently about 85% of the forest is designated as protected. But there are still important areas that are not protected. We are trying to ensure that key remaining primary rainforest in the area will be given protection status and properly managed, for the benefits of the communities, the region’s climate, and to ensure the survival of orangutans and other threatened species.



Globally, demand for environmental services is rising in tandem with population growth. With half the world’s forests already gone, the value of currently remaining forests will only rise. The Indonesian government recognizes this and has begun pilot programs to trade the carbon values of rainforests on international markets.

The Batang Toru Ecosystem could be a source of sustainable revenue for the Batak communities and local governments – if it is left intact. Placing a dollar value on the water it supplies, its role in regulating climate, pollination and other ecosystem services would total about US$3,735 per hectare for a 30-year period, according to the United Nations Environmental Program (UNEP). This is at least the same profit as planting palm oil trees and offers far more long-term benefits, including preserving habitat for hundreds if not thousands of rare and threatened species.