Ecoregional Assessment of Biological Diversity in East Kalimantan

East Kalimantan Ecoregional Assessment: Chapter 2 – Target Ecological Systems
H. Upper Montane Rainforest /Cloud Forest
Description
Photo courtesy of EHB Pollard
Borneo is not particularly mountainous – few of its peaks exceed 2,000 meters above sea
level (a.s.l.). Only five mountains on the island are taller than 2,500m a.s.l. - several of these
are in East Kalimantan or near to it. These include Mt. Makita (Batu Ikeng) near Long
Nawan at 2,987m, and Mt. Siho in Kayan Mentarang National Park, at 2,550m. They are
mainly located along the western spine of East Kalimantan where it borders the Malaysian
State of Sarawak.
The altitude of the interface between Upper Montane Rainforests/Cloud Forests and Montane
Rainforests varies depending on the overall height of the summit of the mountain, its
isolation, and distance from the sea. On larger peaks such as Mt. Kinabalu this interface
occurs at 1,800m whereas on the lower isolated Gunung Palung it occurs at 800m. This
compression effect is referred to as the Massenerhebung Effect (MacKinnon et al.1996). In
this ECA we have adopted 1,800m as the altitude where these upper forest types interface
with the Lower and Middle Montane Rainforest (see previous section).
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