Rainforest Journal

Rainforest Info, Images, and Adventures.

Pasoh Forest Reserve


Pasoh Forest Reserve located in Simpang Pertang, Negeri Sembilan, is an internationally recognized site for tropical forestry research. For researchers, there is a well-equipped Field Studies Center there, called the Pasoh Forestry Research Centre (PFRC) managed by the Forest Research Institute of Malaysia (FRIM). For members of the public who are serious nature lovers, it’s a place to get acquainted with the endangered virgin lowland rainforest of Peninsular Malaysia.

Recently, I had a chance to visit the place again, having been there many times in the past. Comprising a core area of about 600 hectares of primary/unlogged forest within a larger area of about 2400 hectares, this forest is classified as a Red Meranti-Keruing forest, due to the large number of dominant trees from both timber groups found growing there.

pasoh forest reserve

An approximate map of Pasoh Forest Reserve that is managed by FRIM, near the town of Simpang Pertang. The reserve is joined to a (now) secondary hill forest on the right side (note the logging tracks). On 3 sides, Pasoh is surrounded by oil palm plantations.

The forest is joined to a range of hills (highest point at Bukit Palong – 645 m) that up till recently, was also mainly unlogged hill dipterocarp rainforest (a real rarity in Malaysia), but as of the past few years are likely no longer “virgin”, having been subjected to logging. Nothing new there, I suppose.

Getting there

By car, Pasoh is about 2.5 hours’ drive from Kuala Lumpur. If you want to visit the place, please note that it is located within an oil palm plantation (which is accessed via a dirt track that goes through the oil palm plantation). Just head for a small town called Simpang Pertang in the district of Jelebu, and then onwards to Batu Kikir-Kuala Pilah. Half a kilometer out of town, turn left onto a road, and then proceed further until the turn-off onto the dirt road. Locating this dirt road may not be easy, which is why it is mandatory to contact FRIM beforehand about any plans to visit the place. Seek their permission first.

Road into Pasoh

The road into Pasoh is an unsealed road that first passes through oil palm plantations for most of the way, before the rainforest comes into view. It is passable for all vehicles.

Research into forestry dynamics have been conducted at Pasoh since 1970, and there are many forest plots inside Pasoh that have been monitored for years, including a big 50 hectare plot that has been enumerated and monitored for decades, in collaboration with foreign institutions. From 1970-1978, Pasoh was studied under a joint program between University Malaya, the International Biological Programme (IBP), Man & Biosphere Programme (MAB), and the University of Aberdeen, UK. Thereafter, FRIM took over, and developed the field studies center and other facilities there, with help from the Negeri Sembilan Forestry Department.

Points of interest at Pasoh

Today, the forest of Pasoh is of great interest to botanists and nature lovers. It is not a tourist location per se, but a place to educate yourself on Malaysia’s endangered rainforest, and perhaps, to connect with nature. Nowhere else in Peninsular Malaysia has a tropical rainforest been as extensively studied as Pasoh Forest Reserve, and we now have a wealth of material concerning tropical rainforest ecology and dynamics originating from there. Among the interesting features are the Arboretum, the Nature Trail (for visitors), the Tree Tower and Canopy Walkway system (only meant for research), the 50 hectare plot, and of course, the rich flora and fauna found there.

pasoh arboretum

The Pasoh Arboretum, which is about 2 hectares, located near the entrance.

The 2.2 ha Arboretum is located just before the buildings in the Field Research Station, and provides a good place to learn about many of the tree species found in our tropical rainforests. Many of the trees there are tagged and identified. Among the interesting trees there are big Licuala palms and even bigger specimens of Livistona saribus (a type of serdang palm).

livistona saribus

A tall and big Livistona palm in the Arboretum, most likely to be Livistona saribus, which prefers lowlands or swamps.

The 50 ha plot in the middle of Pasoh is where a lot of research has been done. This permanent plot was established sometime in 1985, in collaboration with the Smithsonian Institution, and so far, well over 800 species of trees above 1 cm dbh (diameter at breast height) have been identified and mapped. For such a small area, the tree flora of a virgin forest like Pasoh is exceedingly rich indeed.

nature trail at pasoh

The start of the Nature Trail at Pasoh

old chengal stump

This impressive Chengal (Neobalanocarpus heimii) tree was chopped down 50-60 years ago during logging operations, but the stump remains till today, owing to its hard and durable wood. The trunk is about 1.5 m in diameter, making this tree hundreds of years old when it was felled.

felled gaharu tree

A Gaharu tree that was felled illegally, along the Nature Trail. Illegal felling of Gaharu is a serious problem affecting Malaysia’s shrinking forest reserves. The chopped up bits are characteristic of the method used by the poachers to determine the infected nodes where the fragrant wood resides.

The Nature Trail is located a bit further up opposite the Arboretum, and is a circular looping “interpretive” trail which ends near the start of the Main Trailhead. It can be completed within an hour’s walk or so, and is meant for day visitors to Pasoh. The trail passes through secondary forest for much of the way, but enters primary forest near towards the end of the trail, before rejoining the Main Trail in Pasoh.

pasoh tree tower

The 52m high Tree Tower at Pasoh, which is used for researching the microclimate of the rainforest canopy. It is an extension of the 30m high aluminum walkway system.

The aluminum Canopy Tower and Walkway system was built in the early 1990s to allow researchers to access the canopy and study its microclimate. It consists of 3 interlinked towers with a height of 40m each; one of them was extended a further 12m in height to enable study of the microclimate above the forest canopy. Some time after the construction of the aluminum Tower and Walkway, a wooden canopy walkway nearly 500 meters in length was also constructed, adjoining it. NB: The aluminum Canopy Tower and Walkway is only meant for research, not tourism, but the wooden walkway can be accessed with permission from the FRIM management.

pasoh rainforest

The view from the tower looking towards the range of hills on the eastern side of Pasoh. Note the groups of emergent trees towering over the main canopy, which are probably as tall as the 52m high tower itself (or taller). Pasoh may seem big in this photo, but it is not. Illegal clearance and intrusions continue unabated. From up here though, the forest looks like a paradise.

pasoh panorama

A dead tree stands near the canopy walkway. As I have mentioned elsewhere, tree mortality rates have shot up over the last few decades and became especially acute over the last few years. This problem is clearly seen in mature, unlogged forests or old, secondary forests. The low hills seen in the top left corner of the photo are part of the “sea” of oil palm plantations surrounding Pasoh.

What makes Pasoh unique?

Pasoh Forest Reserve preserves a remnant of the lowland forest that once covered inland Negeri Sembilan, south-west Pahang, and possibly Melaka as well. Being of the Red Meranti-Keruing type, it’s considered a common type of lowland forest, but such arbitrary classifications does not depict the whole picture.

dead tree at the tree tower

Pasoh has a relatively high tree mortality rate, but even I did not expect this big, healthy Kempas tree next to the Tree Tower to die so soon. It was chopped down to prevent any mishaps from occurring. The big tree behind it is a Chengal tree.

What I notice about Pasoh is the abundance of Chengal trees (Neobalanocarpus heimii), abundance of tree species, and strangely, a general absence of bamboo (they do occur, but are rare), even at the outer disturbed fringes. The soil underneath Pasoh is reddish-brown, and weathers into large sized granules, which seem to dry out easily. This type of soil seems more reminiscent of soils in parts of Kedah and Melaka, and may explain some of Pasoh forest’s more distinctive characteristics.

Windthrow (trees getting blown down by strong winds) is a common feature of this area, and indeed, forest gaps are common in Pasoh, made worse by the “island effect” of being an isolated forest surrounded by short stature oil palm plantations, and periods of drought, when the soils would dry out rapidly, leaving weakened roots and trees. The tree mortality rate is quite high here, which explains the lower occurrence of very huge sized trees (if compared with other areas).

ephemeral swamp at pasoh

An ephemeral (temporal) swamp at Pasoh. On flat and low lying terrain in Malaysia, swampy patches like this are very common, especially in areas still under forest cover. These swamps provide a convenient place for wild pigs to wallow, and for amphibians to breed.

This “island effect” has an upside though – for birdwatching. For its small size, Pasoh forest hosts an incredible array of birds; about 400 species have been recorded here, probably squeezed into this fragment of forest with nowhere else to go. Many forest edge and garden species are found here, along with birds that only specialize in undisturbed forest. As for large mammals, there used to be a couple of elephants about 20 years ago, and even tigers were present, but that was 40 years ago according to the rangers. Today, Pasoh is too small to allow most large mammals to survive long term, even if the adjoining hill forest is taken into account. It is still a refuge for many of the smaller mammals, but as the forest continues to shrink, they will be squeezed even more and more into this area.

wild pig activity

Wild pig activity, seen on one of the trails. Wild pigs dig up the soil to search for edible roots, and they also affect the dynamics of the forest undergrowth due to their trampling and nest building activities.

This is still a good place to visit for a day trip, if only to experience what it’s like to be inside an unlogged and undisturbed lowland dipterocarp rainforest within a couple hours’ drive from urbanized KL. There are no uphill hikes here; the terrain is pretty flat and undulating all throughout. It’s hard to believe that such forest is now extremely rare; most of us today are conditioned to see oil palm covered landscapes instead.

For those who like waterfalls, there are a number of waterfalls close by, one of which is the Serting Ulu Recreational Forest, just a few kilometers away. This is a picturesque and serene waterfall, ideal for cooling off, or merely to relax amidst verdant surroundings. There is even a small VJR (Virgin Jungle Reserve) compartment adjoining it. Highly recommended.

Looking back at all the studies conducted at Pasoh Forest Reserve so far, one thing is clear – Many of these studies are of primary rainforest ecology and dynamics, but how much forest (let alone primary forest) do we have now to keep all these data relevant? Are these studies going to be consigned to the museum along with many of our plant and animal species in the future?

I certainly hope not.

For the FRIM page on Pasoh with further details – Go HERE.

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  1. Hi,
    I enjoy reading your writing. And I honestly couldn’t stop clicking from one topic to another. Your writing has helps me a lot in giving me the things-i-must-know.
    From microbiology to environmental studies, and now I’m about to embark in a PhD studies on forestry. I must say I finnaly found something that I really enjoy to dwell myself in.
    However, I notice that ,in some of your writing, you mentioned about how much studies is being done , yet not much changes (for the betterment) of our forest is being carried out.
    I don’t know- but for sure it is frustrating. Although academician/scientists play important role in shaping the health and sustainable environment (esp for our forest) but verily, it’s not them who have the ultimate power. I have met a number of researchers who complaint about their frustration for not being able to implemented/applied what they have studied/discovered into real life. What they have discovered end up as nothing but merely papers ranked by their impact factor. Sometimes I do wonder, will it worth all these crazy work, hardship (spent on research) knowing it wouldn’t change anything much? should I continue stay in this hopeless, underpaid, rigrous field? (Now, as student). What is the point in doing something that (apparently) not benefit others nor myself?
    And yes, soon there will be no more forest for us to study and soon all these data will end up in museum or become meaningless (as it’s) speaks of history instead of scientific idea that once we thought can be used in protecting this valuable natural resource. Tq

  2. @ Amira

    Thanks for your comment. Can’t say much except follow your passion and what brings you real happiness 🙂

  3. Hey mate,

    Superb website. Thank you for providing such essential information in such a captivating manner. Might I ask how, if possible to engage an experienced guide to take a group up to the Pasoh Forest for a bit of education and sightseeing?

    This is what my mates from New Zealand want to get a taste of, aside from the food. But there seems to be a dearth of experienced eco, adventure tourism operators. Can you recommend someone?

    Best regards,


  4. @ Andy

    If you contact FRIM beforehand and your group is big enough to warrant it, maybe they can arrange to provide the services of an officer to give a guided tour.

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