Pasoh Forest Reserve

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Current Site Manager: Christine Fletcher


The Pasoh Forest Reserve (FR) is located on peninsular Malaysia approximately 70 km southeast of Kuala Lumpur. FR has an area of approximately 140 km2, mainly covered with lowland dipterocarp forest and with hill dipterocarp forests in its north-eastern boundary. The core area which is approximately 600 ha within the reserve is still covered with old growth forest; most of the surrounding area has been logged in the past, providing many examples of regenerating lowland forest. Pasoh became a natural ecology laboratory to researchers, mainly from the United Kingdom, in the early 1970s and was recognized under the International Biological Programme by UNESCO. Various research projects were conducted in the field of biodiversity, forest productivity and ecology in collaboration with local universities. In 1977, a total of 1,840 ha was gazetted as Research Forest by its custodian, the State Forestry Department of Negeri Sembilan in recognition of its importance as an international research site for ecological studies. Research activities in collaboration with renowned international research institutions such as the Center for Tropical Forest Science (CTFS, United States) and the National Institute for Environmental Studies (NIES, Japan) have contributed to over 300 published articles and graduate theses/dissertations. The Pasoh Forest Reserve is the best-studied lowland tropical forests in the Southeast Asian region.

Site Description: 

The Forest Research Institute Malaysia (FRIM), together with the State Forestry Department Negeri Sembilan, manages a research station within the forest reserve since 1971. The research station coordinates and facilitates research activities and promotes educational activities for the local community within the forest reserve. The Pasoh base station has dormitory and housing facilities, with a total of seven rooms accommodating up to 16 persons. These are situated in a clearing within the forest together with a small laboratory library for research and reference work. There is electricity, water (pumped from underground) and internet supply at the station. Another four rooms accommodating eight persons are available at the house in Simpang Pertang, the town nearest to Pasoh.

For research purposes, FRIM maintains:

  • a 50-ha permanent tree demographic plot, established in 1985, and censused every five years. All trees >1 cm diameter at breast height are mapped, tagged, identified and measured and counted using the CTFS methodological standards. Data are incorporated into the central CTFS database.
  • five 2-ha permanent ecological plots, established in 1971. All trees >10 cm diameter at breast height have been mapped, tagged, and identified.
  • a 2-ha arboretum with 874 tagged and mapped trees belonging to 279 species from 44 families.
  • three aluminum-alloy towers interconnected with aluminum bridges at 30 m. One of the towers is taller (52m) and houses micro-climate measuring apparatus and carbon-flux equipment for microclimatic and physiological studies at various heights of the forest canopy while the walkways provide convenient access to the canopy for phenological observations and faunal studies.
  • a wooden canopy walkway system (475m long) that connects the aluminum tower system to a wooden tower
  • a guided nature trail totaling 2.3 km with 67 observation points

Rainfall ranges from 1728 to 3112 mm (mean 2054 mm), which is relatively low for Malaysia. A fairly even distribution of rain throughout the year nevertheless permits the development of typical lowland rain forest. Being an isolated forest surrounded by oil palm estates, formation of large forest gaps by windthrow is a fairly common feature at Pasoh.

The history of research in Pasoh Forest Reserve started in early 1961 when early researchers pioneered works mostly in silviculture, ecology and ornithology. Presently, studies at Pasoh consist mainly of long-term collaborative research between FRIM and the two main research partners – Centre for Tropical Forest Science (CTFS) and the Japanese National Institute of Environmental Sciences (NIES). Below are two of the anchor long-term collaborative studies carried out at Pasoh FRS:

  • FRIM/NIES/UPM/FDPM/UTM Joint Research Project (1991–present): A large-scale collaboration between FRIM, National Institute of Environmental Science (NIES), Forestry Department of Peninsular Malaysia (FDPM), Universiti Putra Malaysia (UPM) and Universiti Teknologi Malaysia (UTM). Research areas include assessments and monitoring in carbon stock and change, biodiversity, watershed management, socio-economic studies, database and networking. Numerous publications have been produced from this collaboration including a comprehensive book entitled “Pasoh: Ecology of a Lowland Rain Forest in Southeast Asia”.
  • FRIM/STRI/CTFS-AA Joint Research Project (1985–present): One of the longest lasting and intensive collaboration at Pasoh FR between FRIM, the Smithsonian Tropical Research Institute (STRI), Center for Tropical Forest Science (CTFS) and Arnold Arboretum (AA) at Harvard University. This project is synonymous with the 50-ha long term ecology plot at Pasoh Research Forest which was established in 1985 where all stems ≥ 1cm DBH are measured and recorded every 5 years. Among the significant findings after 20 years of measuring and re-measuring trees is that there is a decline in tree growth rate and increase in tree mortality rates postulated to be due to increase of temperature while seed production has shown significant inter annual variation throughout the census period.

Although surrounded by oil palm plantations, there are still a high variety of living organisms thriving in this forest fragment. The main feature at Pasoh is its floristically rich forest. The 50 ha plot consists of primary lowland rain forest with ca. 340,000 trees >=1 cm dbh identified to species. Out of a total plot tree flora of 820 species, 76 species are known to bear edible fruit. Especially diverse are the wild species of mango (Mangifera, Anacardiaceae, 12 spp.), mangosteen (Garcinia, Clusiaceae, 13 spp.), breadfruit (Artocarpus, Moraceae, 10 spp.) and rambutan (Nephelium, Sapindaceae, 5 spp.).


Although Pasoh today lacks big game animals such as tigers and tapirs, there were recent records of elephants, and a high diversity of small mammals, primates and birds. Faunal diversity includes 112 species of mammals (representing 56% of the total mammal species found in the Peninsular Malaysia), 233 species of birds, 413 species of moths (40 species of which were new records for Peninsular Malaysia), 57 species of termites and 75 species of herpetofauna (including 26 amphibian species and 25 species of snakes).

View the mammals and birds species list for this TEAM site.

The Pasoh Forest Reserve study site (2.98 N 102.31 E) is located about 8 km from the town of Simpang Pertang, approximately 70 km southeast of Kuala Lumpur (140 km by road). It is easily accessible by public taxi from major towns such as Kuala Lumpur and Seremban, as well as directly from the Kuala Lumpur International Airport. To drive from Kuala Lumpur, use major highways and head southeast through Seremban or Kuala Pilah town, or northeast through Karak town. Follow through signboards towards Kuala Pilah and then Simpang Pertang. Travelling time is approximately 2–2.5 hours from Kuala Lumpur or 1 hour from the Kuala Lumpur International Airport.


Latitude: 2.982
Longitude: 102.313