Third Division Swamp Forest
Location:
2°27'-3°10'N, 111°40'-113°02'E; a 150 km strip of coastline from Kuala Igan to Bintulu, extending for up to 45 km inland, Third Division, Sarawak.
Area:
340,000 ha.
Altitude:
Generally below 50m.
Biogeographical Province:
4.25.12.
Wetland type:
11 & 21.
Description of site:
A vast tract of peat swamp forest, much of which is production forest, now largely exploited, with patches of cultivation fringing the coastline and numerous rivers draining the peat swamp. The coastal plain is backed by a ridge of high ground running southwest from Bintulu. The Mukah-Balingian coastal peat is of recent origin, deposited between raised beach lines. During a forest inventory in 1973, the forest in the coastal area of Balingian Forest Reserve appeared to be degenerating (Marsden, l973a). Local rainfall provides the major source of water. The peat swamps drain radially into major rivers running perpendicular to the coastline. The water table lies close to the surface of the swamp, and may be above the surface during the wet season. The water level varies by about 2.65m at Tatau. A salinity of 0.047 p.p.t. has been recorded upstream from Sungei Bawan, 2.20 p.p.t. downstream from Rh. Gelugu, and 7.44 p.p.t. downstream from Balingian.
Climatic conditions:
Humid tropical climate with an average annual rainfall of 2,500-3,000 mm in the Bintulu, Sebuah and Tatau area. The region is exposed to the northeast monsoon, and about 50% of the rainfall occurs during the monsoon season from November to January. The rainfall is, however, relatively high (200-300 mm per month) even during the dry period from April to August.
Principal vegetation:
Peat swamp forest of various types. Mangrove forest and cultivation in adjacent areas.
Land tenure:
State owned (Sarawak State Government).
Conservation measures taken:
The entire area is included within the Igan, Kut-Mudan, Oya Mukah, Sungei Kenyana, Sungei Penipah Retus and Tatau Protected Forests, and the Sungei Sekai, Sungei Bawan and Setuan Forest Reserves.
Conservation measures proposed:
The remaining virgin forest areas should be identified and given complete protection; the remainder should be managed under sustainable forestry practices.
Land use:
Timber extraction and fishing; agriculture in adjacent areas. The site itself has an agricultural potential varying from nil to poor.
Possible Changes in Land use:
The proposed Bakun Dam Hydro Project involves the construction of a dam on the Balui River, 37 km upstream from Belaga. The reservoir created by this dam will flood 71,000 ha (4.7%) of the catchment area of the Balui River above the dam. The hydro-electric station will generate 2,400 megawatts for supply to Sabah, Sarawak and Peninsular Malaysia. Three other major hydro-electric projects have been identified for possible commissioning between 1995 and 2010: the Murum (900 megawatts), Pelagus (770 megawatts) and Baleh (950 megawatts), all in the upper Rajang River Basin. Logging is very likely in the future. The proposed development of the Baran River Club may involve clearance of forest on the Usun Apau plateau and replacement with grassland stocked with exotic animals.
Disturbances and threats:
Over-exploitation of the peat swamp forest and conversion of forest to other land uses.
Economic and social values:
The domed surfaces of the peat swamps mitigate the extent of local flooding, and the swamp forests provide a valuable timber resource which could be managed on a sustainable yield basis.
Fauna:
No information.
Special floral values:
One of the largest areas of peat swamp forest in Sarawak.
Research and facilities:
Forest inventories and soil surveys have been carried out, and the Forest Department has established research plots at Sungei Buloh and Sungei Bawan.
References:
Anderson (1964); DID Sarawak (1979/80); FAO (1974); Kavanagh (1985b); Marsden (1973a & 1973b); Wood (l966a); Yusof & Cheong (1977).
Criteria for Inclusion:
1b.
Source:
Sarawak Forest Department.