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Legal classification    Location & access    Infrastructure    History & management    Settlements and adjacent land-use    Physical environment    Vegetation    Fauna    Exploitation history    Research    Threats & constraints    Special attributes

Last updated: 26 Apr 2005

Survey carried out in October 2000.

Note: In normal usage, the term Sepilok forest reserve is loosely used to mean both the Kabili-Sepilok Forest Reserve (Class VI, the dryland forest) and the Sepilok Forest Reserve (Class VI, the mangrove area). This report covers BOTH  FRs.

Legal classification

Class V I Virgin Jungle Reserves (VJR).

AreaApprox. 5529 ha. (Kabili-Sepilok 4,294 ha and Sepilok 1235 ha.)

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Location & access

The Kabili-Sepilok and Sepilok VJR are situated about 22 km from Sandakan town along Labuk Road. The main access into the VJR is at the Sepilok Orang-utan Rehabilitation Centre where the Mangrove Trail leads to the Sepilok-Laut mangroves, about 4.5 km south. Others include forest trails from the Sepilok Arboretum also link to the main Trail. The western and eastern boundaries are accessible as there are unsealed, oil palm plantation roads close to the boundaries.



The Sepilok Orang-utan Rehabilitation Centre (SORC) is on the northern edge of the VJR. In the north, adjacent to the VJR, is the Sepilok Arboretum where the Forest Research Centre complex is situated. The Forest Research Centre (FRC) and the Orang Utan Rehabilitation Centre are administered by the Sabah Forestry Department and the Sabah Wildlife Department respectively. See aerial photo


The Mangrove Trail stretches about 5.5 km from SORC to the Sepilok-Laut Reception Centre, located in the Sepilok FR (Class VI). There are small bridges and bird-watching towers built by British volunteer groups brought in by the SORC management.


There are long-term research plots in the VJR which are managed and monitored by FRC.


History & management

PastIn the days of the Chartered Company, Mr. Pryer owned a coffee plantation on the lower Kabili River, in the southwest of the VJR. This was abandoned in about 1910 following an outbreak of disease amongst the labourers and a slump in the coffee trade. There was another coffee plantation- owner unknown- in the southeastern portion. A graveyard is said to exist on the lower left bank of the Kabili River in Compartment 18. Occasional coffee trees could still be seen in the area in the late 1960s. This, and probably other areas with timber fringing the rivers, was logged around 1890-1900, maybe on a highly selective basis (floaters only?).


This, and probably other areas with timber along the rivers, was logged some 90 to 100 years ago probably on a highly selective basis. Two of the earliest known logging operations were in 1911 and 1929. Earlier records relating to exploitation and other activities are not available. During the Second World War, the Forest Department personnel stayed inside the VJR.


Low impact forest exploitation by means of hand logging and by tractor were conducted in the northeast and most of the southern part of the reserve from 1919 until it was discontinued in 1957. It is estimated that about 24,262 m3 of timber from 670 ha were extracted during that period. In 1948, several hundred hectares of forest in the northern part of the FR were silviculturally treated by removal of woody climbers and non-productive trees that hampered the regeneration of potentially commercial trees, such as Shorea johorensis, Parashorea tomentella and Eusideroxylon zwageri. The effect of this liberation treatment on the forest stand in this area is unknown. However, the treated forest is structurally comparable to the other old growth forest in the region. Since 1957, the primary functions of the Kabili-Sepilok VJR have been forestry research, and simultaneously, the preservation of some of the major forest types of Sabah.


In 1964, the Game Branch of the Department maintained a station in the north (Compartment 4) for the rehabilitation of orang-utans. The Branch has since been made into a department by itself, the Wildlife Department, and the station came to be known as the Sepilok Orang-utan Rehabilitation Centre.

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CreationKabili-Sepilok VJR was gazetted in 3 phases:

  • In 2/2/1931, some 2,334 ha was gazetted under Notification No. 80/1931. This area encompassed much of the drainage of the Kabili, Sepilok Kecil and Sepilok Besar rivers.

  • In 1938, another 1,874 ha on the eastern side was gazetted under Notification no. 322/1938.

  • In 1965, a further 264 ha was added on the north and south-east under Notification No. 617/1965.


In 1930, the main reserve was organised as a series of rectangular compartments numbered 1 to 18. In 1956, compartments 19 to 21 were established east of Sg. Sepilok Besar.


The VJR is managed by the Sabah Forestry Department and no logging has been allowed since 1957. In 1984, the VJR was formally gazetted as a Class VI Forest Reserve in the Forests (Amendment) Enactment, 1968 (No. 4/1984).


Management responsibility—Under Sandakan District Forestry Office. The SORC and its surrounding forest is managed by the Wildlife Department. All matters of forest research is managed by the nearby Forest Research Centre.


Boundary matters—Demarcated.


Management plan—None. A development plan for the Sepilok-Laut Reception Centre was prepared by Mr. Martin Paul-Vogel and approved by the SFD. The plan is used to coordinate the development of the centre into an area for nature recreation and education. Funding for the 1st phase of the development was provided for by the Federal Government under the 8th Malaysia Plan.


Current use—Forest ecology and wildlife research, environmental education and nature tourism.

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Settlements & adjacent land-use

The VJR is surrounded by poultry farms, fruit orchards and small-scale oil palm plantations in the north, by large oil palm estates in the west and an industrial zone (known as the Seguntur Integrated Timber Complex) in the east. The Sepilok Arboretum, just north of the Kabili-Sepilok VJR, is being developed as a centre for environmental education, nature recreation and tourism.


Along Jalan Sepilok, the road that leads into Sepilok and ends at the Sepilok Orang-utan Rehabilitation Centre, are 3 B&Bs and two resorts.


Physical environment

Topography—The sandstone ridges give Sepilok its dominant characteristic. These rise rapidly in some cases not far from the mangroves. The most hilly areas are in Compartment 19 and 20 where the Sepilok Trig point (168 m) is located. The south-west corner of the VJR is gently undulating country not exceeding 30 m.


Hydrology—In Sepilok VJR (mangrove), Sg. Arang, Sg. Sepilok Besar, Sg. Sepilok Kecil, Sg. Cina, Sg. Pandan, Sg. Pakis, Sg. Suana, Sg. Kabili and Sg. Carib drain to the sea in the south. Sg. Gum Gum drains to the northwest while Sg. Sibuga drains to the northeast.


Soils—The main soil associations are the Silabukan, Lokan, Maliau Associations, with Weston in the mangroves and a small patch of Rumidi Association.

For soil map, click here.

Geology—Most of the VJR has been mapped as Sandakan Formation. It consists of mudstone, sandstone and some siltstone with rare thin coal seams. Its age is Upper Miocene or younger. The Upper Miocene beds of this part of Sabah occurs in basins modified by faulting. A cliff in the headwaters of the Sepilok River appears to be due to a fault trending northwest, roughly parallel with two scarps on Berhala Island, one of which is apparently due to faulting. Around the headwaters of Sepilok and Gum Gum Rivers curving ridges show the presence of a pitching syncline or basin that has apparently been cut off by a north-easterly fault.


Of the rock types, mudstone is the most abundant in the Sandakan Formation accounting for about 50%. Mudstone beds with thin lenses of siltstone may be as much as 150 m thick, while thinner beds from a few cm to about 6 m thick are inter-bedded with sandstone and siltstone. The mudstone is mostly grey to dark grey or greenish grey in colour. (Mudstone generally gives rise to undulating low hills of small amplitude).


Sandstone occupies about 40% of the Formation and forms prominent scarps and ridges in Sepilok. The most prominent scarp is that to the southeast of Compartment 26. The larges number of ridges in the ridges in the VJR suggest that sandstone makes up more than 50% of the rock type in Sepilok. The sandstone is soft, grey to bluish grey weathering yellow brown.


Siltstone occurs in thin beds within the sandstone  and mudstone. These beds are usually up to 60 cm thick, rarely larger than 3 m. It is grey to bluish grey, mineralogically similar to the sandstone and weathers in the same way.


Meteorological data—The nearest met station is at Sandakan Airport, just a few kilometers east of the FR. In the period 1976–1995, Sandakan airport had a mean (± one SEM) annual rainfall of 2929 ± 134 mm and mean annual temperatures in the range 26.7–27.7°C. The rainfall is generally influenced by the northeast monsoon, which normally occurs between November and February in the region, and April is the driest month (mean 92 ± 20 mm).

Map of met. stations    Rainfall map


See current vegetation map here

See natural vegetation map here

See satellite image here

The following is an excerpt of Reuben Nilus's PhD thesis. The article stays fairly true to the original with minor changes.

The forest is mainly Parashorea malaanonan / Eusideroxylon zwageri  type forest, classified as Type B forest by JED Fox. Three major forest types have been identified at Kabili-Sepilok VJR and their distributions co-vary with the distribution of the different soil types and landforms. The lowland dipterocarp forests overlying the soils of the Silabukan and Lokan associations are described here as alluvial and sandstone hill forest, respectively. The forest that overlies the soils of the Maliau association is heath or kerangas forest.


Fox (1973a) described the alluvial forest as dominated by large dipterocarps reaching a canopy height of 37–45 m or more, and diameter at breast height > 70 cm. In this forest, Parashorea tomentella and Shorea johorensis (both Dipterocarpaceae) are the most abundant canopy species with Eusideroxylon zwageri (Borneo ironwood, Lauraceae) as a large and common lower canopy species. However, these species are totally absent from the sandstone hill forest where the dipterocarps Shorea multiflora, Dipterocarpus acutangulus and Shorea beccariana are the most abundant large trees. The canopy of the sandstone hill forest is about 34–40 m and occasionally Dipterocarpus acutangulus emerges above canopy height.


The kerangas forest consists of two subtypes; Shorea multiflora/Tristaniopsis merguensis (large crown) forest and T. merguensis/Garcinia miquelii (small crown) forest. In the former subtype, elements of the sandstone hill tree flora occur on many of the ridges where most of the abundant large trees are Shorea multiflora and Ixonanthes reticulata. In the lower stature kerangas forest, the area is almost purely dominated by Tristaniopsis merguensis (Myrtaceae).

Read more about mangroves.

Read more about kerangas.


Being a protected forest and a tropical forest research site for a long time, the VJR is a refuge for small mammals. Large animals have disappeared from the VJR. (Reports show that elephants disrupted research in the 1930s when they destroyed seedlings planted in the VJR.) Mammals such as orang-utan, gibbon, macaques, mouse deer and squirrels (including pygmy squirrels) can be seen or heard. Recent population estimates of orang-utans in the VJR is between 100 and 200 individuals.


The VJR is also a very good site for bird-watching.


Exploitation history

The area in the northeast, Matalau River valley, was loged prior to 1919 by Kim Eng Watt Bros. They used hand logging methods and hauled the timber from no further than half a mile to the river. Chin Piang Syn logged the same  area with tractors during 1953-55. Sg. Arang in the southeast, was logged by Lai Fook Kim in 1956 using hand handling to locomotives. An area adjoining Kg. Bambangan Native Reserve in the southeast, along with Sg. Masbud and Sg. Lolong, was logged by Ahmad Karim in 1955-56. Other recorded exploitation included Compartments 13, 14 and 15 by North Borneo Trading Co. Ltd. in 1938-42. This was on an area treated between 1935 and 1938 by regeneration improvement silviculture. Some 400 acres were illegally logged in 1967 in the northeast.



Research on the forests of this VJR is extensive. Below are some information on historical research activities.


  • In 1931, a valuation survey was conducted to determine the growing stock. It was a disappointing figure of 452 cubic feet per acre.

  • In 1932, 58 seedlings of mora, Chlorophora tinctoria, from Trinidad were planted in Compartments 15 and 18 on the left bank of the Kabili River. In October, almost 2,000 seeds of belian were line-planted in Compartment 15. The seeds were collected from Sg. Kretam Besar.

  • In 1934, Regeneration Improvement Felling was carried out in Compartment 15. The southern half of Compartment 15 was cleared and planted with Liberian coffee in 1894. The mora seedlings planted in 1932 survived. About 500 penaga seeds were planted.

  • In 1935, 3 sample plots were established in Compartment 4, 15 and 18. Regeneration improvement felling was carried out in Compartment 14, 15 and 18. Merbau seedlings were planted in Compartment 15. Seedlings of keruing (not specified which), yemane and penaga were planted in Compartment 18. Rotan saga was planted in both Compartment 15 and 18.

  • In 1936, Regeneration Improvement Felling was carried out in Compartments 16 and 18. In Compartment 15, seedlings of belian, merbau, majau, penaga (along rivers), kayu cina and kayu chendana were planted. In Compartment 18, tengkawang, rotan saga (from Banjarmasin, Indonesia) were planted. Limpaga was planted in Compartment 4. Wild boars and elephants posed numerous problems to the planting experiments. A linear (Dipterocarp) plot along the path in Compartment 14 was established.

  • In 1937, cendana, kayu cina, merbau and rotan saga were planted in Compartment 15. Limpaga, pine, and merbau were planted in compartments 4, 7 and 18 respectively.

  • In 1938, Regeneration Improvement Felling (CG 2) were conducted in Compartment 14 and 18. Logging was carried out by NB Trading Co. Ltd. from April to December. Agathis alba (menghilan) and Dacrydium sp. (tempilas) from the Sinsuron River were planted. Wild boars, buffalos, elephants and porcupines posed problems to research activities, especially planting experiments.

  • In 1939, Regeneration Improvement Felling were conducted in Compartments 13, 16 and 18. Harvesting was carried out in Compartment 14, 15.

  • In 1940, Regeneration Improvement Felling (CG2 & CG1) were conducted in Compartment 13.

  • In 1948, Melaleuca leucadendron was planted.

  • In 1949, Selective Improvement Felling, for the benefit of the established young stock, were carried out in Compartments 13, 14 and 15. This included climber cutting, felling of Ficus-bound trees and removal of unwanted trees by poison girdling. Small-scale planting of balsa (Ochroma lagopus) (seeds obtained locally) and Melaleuca leucadendron (seeds from Hongkong). Only 79 out of 177 transplants of balsa  survived, and 295 out of 584 transplants of Melaleuca leucadendron.

  • In 1950, plantings of Cola acuminata, the African cola nut, were conducted on a small scale. Seedlings were seriuosly damaged. The seeds were obtained from Sapong Estate from trees planted there since the early 1900s. Germination for balsa was poor and transplants were damaged by deer. Melaleuca leucadendron, planted in 1948, continued to flourish despite trampling damage by tembadau. Average height after two years was 10 feet.

  • In 1955, a half acre plot of Dipterocarps, mainly Shorea argentifolia, along the path in Compartment 15 was established.

  • Three 10-acre (approximately 4 ha) plots were established by JED Fox in the Kabili-Sepilok VJR in June 1968.

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Most of the Department's research records were lost during the Japanese Occupation and the fire of 1961.


More recent research work:

  • In 2000, a multi-disciplinary research project, Biotic Interactions in Tropical Rain Forests (BITRF), began. It was headed by Aberdeen Univeristy, Scotland, with other principal investigators from various universities in the United Kingdom. One of the major sources of funding was from the British Ecological Society. Reuben Nilus, Ecologist at the Forest Research Centre, was the main local collaborator for this project. About five PhD student were involved. Dr Collin Maycock supervised and coordinated field research work. He also carried out studies on the dispersal of dipterocarp fruits. The main project ended in 2003 but smaller studies continue to be carried out. Reuben Nilus' PhD research was on the effect of edaphic variation on forest structure, dynamics, diversity and regeneration in Kabili-Sepilok VJR.

  • The Ecology Section of the Forest Research Centre has permanent sample plots within the Kabili-Sepilok VJR over different soil types, i.e. alluvium, sandstone ridge and kerangas.

  • A two-year doctoral research on the activity and habitat use of Lesser Mouse-deer (Tragulus javanicus) was carried out in 1998-2001 by Hisashi Matsubayashi from Tokyo Institute of Technology. The muse-deer was thought to be a nocturnal animal. However, this study showed that individuals forage mainly during the day. Another finding suggests that mouse-deer use food resources in forest gap areas.

  • The Kabili-Sepilok FR was one of the sites for a 3-year doctoral research by Carsten A. Bruhl, on the effects of tropical rainforest fragmentation on the leaf litter ant community. The other sites were Kebun Cina Forest Park (Sandakan) and Danum Valley Forest Reserve.


Threats & constraints

Fire—The risk of fires occurring near the western, northern and eastern boundaries are high during long droughts. Fires are normally started by landowners clearing their lands. During high fire risks periods, staff from the nearby Forest Research Centre do daily monitoring of the boundaries to look out for fires and to advice landowners against using fire to clear their lands.


Encroachment—The two VJRs are relatively safe from illegal logging activities. However, there were occasions of illegal logging in the southwest of the VJR in 2000 and 2001, affecting research plots. Logs were presumably transported out of the VJR from the mangroves. There are also evidences of hunting of small mammals within the VJRs.


Special attributes

The various forest types and the supporting research and nature educational facilities makes this VJR very special indeed. The tourism potential is very good. The SORC collects more than RM 1 million annually from ticket sales from about 80,000 visitors. It is with this in mind that the Sabah Forestry Department is developing the Sepilok Arboretum to provide another destination for visitors. The Rainforest Interpretation Centre, with its exhibition halls, gardens and surrounding forest, will be a major tourist destination in the near future.

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