Potential and natural wealth contained in the region and outside Siberut National Park area is very varied. There are 7 types of ecosystems on the island of Siberut with various types of flora and fauna that live in it, the type of ecosystem in Siberut, namely:
Primary dipterocarpaceae forest
Located in areas with altitude and hilly. Forest canopy is generally about 40-50 m by 50 m height trees are still commonly found. Dominant tree species are Dipterocarpus, Shorea, Vatica and Hopea. Also found in other species such as Palaquium (Sapotaceae) and Hydnocarpus. In this forest type LIPI (1995) has recorded 81 species and 59 genera.
Primary Mixed Forest
Found on the slopes and lower hills below primary dipterocarp forest. Many tree species are represented but no one was dominant. Families which are common are Euphorbiaceae, Myristicaceae, Dilleniaceae, Dipterocarpaceae and Fabaceae.
Former Felling dipterocarp forest regeneration
Which is a ex-forest of several timber companies that once operated in Siberut. Its area includes the North, South, East and Siberut. Some areas are dominated by pioneer plants such as Macaranga, Trema and Neolamarkis.
Freshwater Swamp Forest
This forest type is limited and specific tree flora, often dominated by Terminalia phellocarpa. There are many valley-valley and surrounding watershed. The most extensive wetlands and is in the village / hamlet is located on the east coast. Ground flora is dominated by the palm, feathers rattan, pandanus and aroid.
Mangrove Forest
Found along the coastline and islands on the east coast. The area has the largest mangrove forest such as the Teluk Katurai (Southwest Siberut), Saliguma (Middle Siberut), Cimpungan (Middle Siberut), Pokai (North Siberut). In general, Rhizophora is a genus of major and widespread in the mangrove groups on the island of Siberut. Results of research ever undertaken by the Siberut National Park (2001) has recorded as many as 23 species of mangroves, 14 species are typical mangrove species and 9 species of mangroves is a group of non-typical.
Sago Swamp Forest
There are 2 species in Siberut namely Mexroxylon sago and Metroxylon rumphii sago in Siberut has a tremendous growth rate, reaching 12 meters in 8 years and grow to 18 meters, higher than most other regions.
Forest Beach
Encountered along the west coast of Siberut island. Common species are Casuarina equsetifolia, baringtonia sp, Hibiscus tiliaceus and Pandanus sp.
Based on planimetric measurements and map the results of satellite image interpretation (LIPI, 1995) forest cover in Siberut, namely: 76% of primary forest, secondary forest that has been exploited by 6.5%, 5% swamp forest, thicket in the plain 5.97% the remaining four , 53% is agricultural land.
