Bidu-bidu Forest Reserve

Bidu-Bidu FR is situated in the Beluran District, about 35 km northeast of Telupid town and 125 km west of Sandakan. It is surrounded by all-weather unsealed road except in the northwest. The FR is easily assessable via the road network of the surrounding oil palm estates. However, the main access into the FR would be the gravelled roads heading towards Kg. Nangoh, towards Kg Kiabau in the west and from the Pamol Estate in the north. 

None.

Creation—Bidu Bidu FR was first gazetted in 1972 as a FR. It was later classified as Class I FR in 1984.

Management responsibility—Mukim Liwagu, Telupid District Forestry Office.

Boundary matters—The boundary has yet to be demarcated. However, yellow FR signs are put on trees adjacent to oil palm estates.

Management plan—None.

Current use—None.

The FR is surrounded mainly by oil palm plantations. The main ones are Duta Plantations, IOI Plantations, Sapi Plantations, Adabi Plantations and PAMOL. There are a number of villages surrounding the FR. The main villages are Kg. Kiabau (about 2 to 3 km west of the FR), Kg. Bakong Bakong (in the northeast) and Kg. Toniting (in the southwest), with about 100 households in each village. Other villages are Kg. Bius and Kg. Nangoh. 

Topography—The FR is generally hilly with very steep slopes. Mt. Bangau Bangau (648 m) is the highest peak in the FR.

Hydrology—The area is well-drained owing to its hilly terrain. It is a catchment for the Bangau Bangau and Terusan Sapi rivers. These rivers are tributaries to the larger Labuk River which flows outside the FR from the southwest to the north. The upper reaches of the Bangau Bangau River is located near the centre of the FR and flows eastwards.

Soils—Predominantly Bidu Bidu Association. Scattered Mentapok Association. The Mentapok Association covers less than 10% of the FR where the slopes are more than 25°. Binalik Association occurs in valleys in the north.

Geology—The whole of the Bidu-Bidu FR is formed from intrusive ultrabasic igneous rocks. The plateau in the hills might represent the flat top of an intrusion.

Meteorological data—See Trusan Sapi Met. Station data.

Most of the FR (about 80 to 90%) is still covered with good ultramafic forest with the dipterocarps dominant in the main canopy.

The natural vegetation of Bidu Bidu FR is generally intact, and is classified as ultramafic forest, growing on soils of the Bidu Bidu Association. Common dipterocarps include Dipterocarpus lowii, Shorea laevis, Hopea beccariana, Shorea atrinervosa, Shorea multiflora and Shorea smithiana. The most dominant dipterocarps were  Dipterocarpus lowii, Shorea atrinervosa and Shorea platyclados. At elevations above 300 m, Gymnostoma sumatrana is the most common non-dipterocarp species.

1. Lowland ultramafic forest

A total of 18 dipterocarp species were recorded from sixteen 0.1 ha plots: 3 Dipterocarpus spp., 2 Hopea spp. and 11 Shorea spp. The most common dipterocarps are Shorea smithiana, Shorea platyclados, Shorea atrinervosa, Shorea multiflora, Dipterocarpus lowii and Hopea beccariana. Koompassia malaccensis and Palaquium gutta are also frequently found in the FR. 

At elevations above 300 m, Gymnostoma sumatrana becomes increasingly common. Slipper orchids (e.g. Paphiopedilum hookerae) are present around 415 m in the rocky conditions of the first peak towards the Bangau Bangau trigonometric station. 

Climbing bamboo is abundant in disturbed areas in the west and southwest, and in the burnt areas in the east.

2. Upland ultramafic forest

The main tree species in this forest type were Dipterocarpus lowii, Shorea micans and Shorea laxa. Other dipterocarps are Hopea ferruginea and Shorea laevis. The highest peak in the FR, Mt. Bangau Bangau, and its nearby forests were not covered during the ground survey due to accessibility problems.

3. Kerangas forest

Hopea ferruginea and Shorea revoluta represent the most common dipterocarp trees in the kerangas forest of Bidu Bidu.

• • Dipterocarpus applanatus (1)

  • Dipterocarpus geniculatus (1)

  • Dipterocarpus lowii (1, 2)

  • Hopea beccariana (1)

  • Hopea ferruginea (2, 3)

  • Hopea wyatt-smithii (1)

  • Shorea acuminatissima (1)

  • Shorea andulensis (1)

  • Shorea atrinervosa (1)

  • Shorea faguetiana (1)

  • Shorea kunstleri (1)

  • Shorea laevis (2)

  • Shorea laxa (2)

  • Shorea micans (2)

  • Shorea multiflora (1, 2)

  • Shorea ovata (1)

  • Shorea platyclados (1)

  • Shorea revoluta (3)

  • Shorea smithiana (1)

  • Shorea superba (1)

  • Shorea venulosa (1)

  • Vatica albiramis (1)

  • Vatica dulitensis (1)

No survey has ever been carried out in Bidu Bidu FR. Although the ultramafic forest of Bidu Bidu is not known to be suitable orang-utan habitat, sightings have been reported in 1998. There were also signs of sunbears, wild boars, mouse deer and barking deer.

An aerial survey was conducted in the FR (sometime 2002 and 2003). This was part of a statewide orang-utan census carried out by HUTAN (an NGO based in Sukau, Kinabatangan) and the Sabah Wildlife Department. Orang-utan population density was 0.077 individual per square kilometre. In the early 1980s, the estimated population was 130 individuals. This 90% decline may be the result of land conversion of all the lowland MDF surrounding the FR to agriculture, as well as hunting pressure (see below and pictures).

Other than occasional botanical collecting trips and cursory floral surveys, there has been no systematic biological research carried out.

Fire—About 10-20% of the FR was badly affected by fire during the drought of late 1997 and early 1998, especially along the boundary adjacent to private lands and large oil palm plantations.

Encroachment—At Kg. Kiabau, there were signs of land clearing in 1999, probably for agriculture, next to the FR boundary but this was not observed during the survey. There were also signs of illegal logging close to the forest-fire boundary roads. The FR is clearly a popular area for hunting as seen by the numerous snares, traps and spent shotgun shells observed during field surveys.

The FR is a very important area for the conservation of ultramafic forest in Sabah. It harbours many interesting plants, many of which have yet to be described as there has not been any major botanical expedition to this area.

The Bakong Bakong Waterfall is a local attraction. It is situated near the northern boundary of the FR, adjacent to oil palm plantations. Basic facilities was funded by the Ministry of Tourism in 1998. During the survey, the recreation area was in good condition except for the vandalised toilets.