Gunung Leuser National Park (TNGL) The flora and fauna of Bukit Lawang Mountain and lowland forests are breath taking. Both are vitally important genetic resource and wildlife habitat. The "green gold" Bukit Lawang is situated at the eastern side of Gunung Leuser National Park (TNGL). This jungle is part of a larger section of jungle known as the Leuser Ecosystem. This region has an area of 2.6 million hectares which includes the area around TNGL which serves as a buffer zone.