Rainforest Journal

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The tualang tree or Koompassia excelsa

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The Koompassia excelsa tree is among the tallest trees in the world, and also one of the most prominent trees in the tropical rainforests of the Sunda Shelf. It is found in Sumatra, Borneo, South Thailand, and Peninsular Malaysia. The grey, whitish bark of the tree, large bole, and often handsome crown makes it stand out amongst the other trees (usually). It is known by different names in different regions – Mengaris in Brunei and Sabah, Tualang in Peninsular Malaysia, Sialang in Indonesia, and Tapang in Sarawak. The name tualang comes from the Malay words of tua – old, and helang – eagle.

buttress roots of the tualang tree

The buttress roots of the tualang

In Peninsular Malaysia, the tualang tree is only found north of an imaginary line that connects Kuala Lumpur (KL) with Kuantan. It has never been found south of that “line” for unknown reasons. If you drive north towards Frasers Hill, you should be able to see some small specimens in the forests of the lower portion of the Main Range, although they are not conspicuous.

I’ve not noticed tualang trees in the forests north of KL on the way to Genting Highlands. They only seem to appear after the boundary with Pahang is crossed (especially around Bentong). That said, tualang trees are not found in higher altitudes above 500 meters asl. It is mostly limited to lowland forests up into the lower portion of hill dipterocarp forest.

Looking up a tualang

Looking up a tualang tree from the base.

The tualang is a member of the legume or bean family. Maybe surprisingly, it is not a dipterocarp. There is another closely related species, the Kempas, or Koompassia malaccensis. The kempas is a big tree widely distributed throughout the country, in all lowland forested areas, especially near riverine areas, although it does not grow as large, nor as tall, as the tualang.

There are legends and lore regarding the tualang tree. Aborigines believe this tree is inhabited by spirits, and it is often left alone in heavily logged areas for that reason. Of course, it being the favorite tree for the Asian Giant Honeybee (Apis dorsata) to build their nests on, is part of the reason why the tualang is often left alone. The bees choose the tree for its smooth bark which is tough for predators like the sun bear, to climb.

Its wood is hard, but decays quite rapidly unless treated, which means it doesn’t have much commercial value. However, as logging has stripped out virtually all the valuable timber there is left, even tualang trees these days are fair game to logging companies.

giant tualang tree

Giant tualang tree by the roadside in Kelantan, about 60 meters in height, at least. Sights like this were common in the past, but getting much rarer these days. This tree stands as a relic of the original forest that used to stand over here. Note the size of the tree in comparison to the cars on the road beside it.

Tualang trees can grow more than 80 meters in height, but this is largely limited to Bornean specimens; more specifically Sabah specimens. Sabah’s rich volcanic soil (in the eastern half) produces very tall and large trees of all species; not just limited to tualang. However, Foxworthy (a British forester conducting work largely in the then Malaya during the 1920s) presumably found a tualang 80 meters tall somewhere in Peninsular Malaysia. This find is intriguing, as all the tualang trees I’ve seen here in Peninsular Malaysia (and I’ve seen a lot) have never really exceeded 50-something meters in height, at most. However, the Sabah specimens are really awesome in height and size, as this little known (but excellent) link, points out, obviously due to the lengthy boles (trunks) of the trees there.

Tualang or mengaris tree

This tualang tree is probably one of the southernmost occurances of the species in Peninsular Malaysia. The tree was spotted south of Karak, close to the limiting “line” that was mentioned above.

Sadly, as most of Sabah and Kalimantan have already been logged out, there is really no way now to find out if tualang trees that exceed 90 meters in height really did exist or not. In Pahang, north Perak, inner Kedah, and Kelantan, tualang trees are very conspicuous, even by the roadsides. You will certainly be able to spot them in many a secondary forest or even in overgrown, old rubber plantations where the original loggers or forest clearers have not bothered with cutting them down, 40 or 50 years ago. You will also be able to see young tualang trees grown in the grounds of FRIM. Up north in Perak and Kelantan, the locals often nail wooden “ladders” up trees that have honeybee nests, to harvest the honey. A dangerous process worth viewing, if you get the chance.

Flowering occurs once every few years, often during mast flowering periods (when other trees in the rainforest are also flowering). The flowers are small, and yellow colored, often taking up the entire crown of the tree. It is not a common occurrence (at least back then), so consider yourself lucky, if you have seen a tualang flowering!

Tualang tree

This picture illustrates the fine crown structure that is commonly observed in tualang trees. This photo was taken years ago when I was at Kuala Koh, Taman Negara.

Another curious aspect of the tualang tree is it sheds its leaves during February-April. However, as the global climate is so variable these days, I won’t be surprised if tualang trees now shed their leaves outside this period. It certainly varies from place to place.

This deciduous behavior is not really common in the evergreen rainforests of Malaysia, so it may indicate the tualang being a “relic” of a more variable, drier climate in the past. Certainly, we know that in the last Ice Age, there were a lot of open woodland areas and the tropical forests then, were not as “tropical” in the sense of the word, as they are today. When tualang trees are in deciduous mode, the lowland rainforest from the air looks peppered with their whitish, fluffy crowns devoid of leaves, and you can easily pick them out from a helicopter.

In Thailand, there are petrified trunks of an ancient cousin of the tualang tree that were found by accident in 2003. Today, these fossilized trunks are preserved for tourists to view at the Ban Tak Petrified Forest Park. These are some of the best preserved and largest fossilized tree trunks in the world to date. Scientists estimate the heights of some of these trees to be well over 100 meters tall, making them one of the tallest trees in the world alongside the redwoods – if they were growing today.

It might be interesting to know that another tree with similar dimensions to the tualang, the Mengkundur or Tetrameles nudiflora is also commonly associated with the tualang where it is found and often mistaken for it as well. The mengkundur tree grows to huge size and develops large buttresses, just like the tualang, and seems to be restricted to drier areas of Peninsular Malaysia (like the tualang too). The mengkundur is also common in the drier states of Negeri Sembilan and Malacca (but the tualang is not found there). All these are further evidence of past climatic differences between then, and now.

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3 Comments

  1. Greetings, thanks for the great read! Love reading about these really stately, outstanding native trees. Long may they live and prosper!
    Can you advise of any other outstanding native trees noted for honey production in the Malaysian/South East Asian area?

    With regards,
    Robin

  2. How long can the Tualang tree survive on the average as they seem to live very long. Can we tell the tree is dying or shedding leaves. The tree in my estate in Pahang, Malaysia seem to be drying up as some of the barks from the part of the tree are falling bit by bit dispite of the rain recently. Can a tree of this size (easily over 150 feet) died because of the recent dry season(2 to 3 months without rain). Can anything be done to save the tree?
    APPRECIATE IF YOU CAN GIVE ME SOME ADVICE. THANKS

  3. @ Edward Kam
    I suggest you contact an aborist from FRIM but usually they will need to take a good look at the tree to determine the problem. I’m sorry to hear that the tree appears to be dying, if the bark and branches are falling off. Normally, tualang trees are adapted to handle the dry season at the early part of the year, hence why they shed their leaves every March-April. But jungle trees often do not fare well if left isolated without their original neighbours.

    Also, in recent times, trees appear to be dying worldwide at unprecedented rates. Even data from FRIM is indicating our forests do not regenerate as well as they should, and this is further reason not to log them. I have talked about this phenomenon of trees dying here. This is a cause for concern because of its seriousness, but most people out there are not aware of this problem. In temperate countries like USA, people are reporting many cases of dying trees.

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