The Big Trees

Rengas-attack

2008-01-26T00:28:00.000+08:00

Another itchy and sleep-less week, this time not of the ticks but the notorious Rengas, a plant in the mango family (Anacardiaceae). Urushiol, an oil found mainly in the Anacardiads, causes an allergic skin rash on contact. Unlucky ones, like me, have worse reaction. But some people are even sensitive enough to get allergic reaction just from eating mango!

Just by brushing against the leaves. As bad as tick bite, if you can imagine.

Urushiol-induced contact dermatitis

The name Rengas actually refers to trees in the genera Gluta and Semecarpus. Here I refer the name to Gluta wallichii (I have been using this name to curse, and it really sounds like bad words). The Wallich's Rengas is actually quite common in our forest, especially at BTNR (70 big trees recorded in my survey), and they can grow quite big (the biggest Rengas I recorded is 78cm in diameter). However, we normally came across (and "kissed" by) saplings of our height. It is not difficult to spot them. Just look out for "black spots" (dried sap), just like those on mango skin.

Leaves of a Rengas sapling, ca. 30cm long (smaller and stiffer in big trees).

Some vegetative characters to identify Rengas.

Rengas' bark fissures like Seraya, but normally scattered with its infamous tell tale sign. Don't anyhow hug a "Seraya" if you are not sure what it is!

It's rare to find them fruiting, like most other rainforest trees. But if you see something like this in the future, it could be Rengas fruit. Picture here is the Rengas-like fruit of Swintonia schwenkii, a cousin of Rengas. See here for a dried Rengas fruit taken by lekowala at BTNR.

It's my laziness (of not wearing long) to be blamed for my rash, not Rengas. After all, at least we can spot a Rengas and avoid it, can't do that on ticks.

No matter what, I still love mango and cashew nuts.

How big can a forest tick grow?

2008-01-18T21:09:00.000+08:00

According to Wikipedia, ticks undergo a lifecycle of several stages. Those we encountered (and got bitten most of the time) are the nymphs (ca. 1-2mm) and some perhaps larvae. So, just how big can a forest tick grow? I was quite intrigued by this question as I never got bitten by an adult one before. Actually, I'd never want to be bitten by one as I can't imagine something as big as the adult dog ticks (ca. 5-8mm) I used to remove from my dogs crawling over and penetrate my skin - unthinkable!

I was lucky enough not to get bitten by any tick yesterday (even when I walked almost the whole reserve, as opposed to the day I last work there - only in a 20m x 20m area) yet caught an adult which was "trying to feed on my pants"!

As big as a dog tick, just flatter and more brownish. My poor North Face Paramount.

Tough sucker, won't let go easily and need to be removed carefully

This is why - barbs along the mouthpart!

Rather cute, actually. Now I decide to name it Pantsy (for simple reason).

On it's back and mummified. R.I.P., Pantsy. Never suck pants again in your next life.

tick-away

2008-01-15T00:59:00.000+08:00

What a name to restart this blog in 2008. My time is really ticking - no manuscript (yet) after almost one year of the completion of Big Tree survey - everything has been just ticking along slowly (ticking over). I need to find the very thing that makes me tick and be productive. The eleventh hour gets a tick for that but it is also unhealthy.

Anyway, productivity aside, I was really ticked off by the way the forest welcomed me back - its very own TICKS, some 50 or so of them! These creatures, albeit tiny, gave me unforgettable love bites that make me wish that I can cut off my limbs! My body is so allergic to their saliva that I couldn't sleep for the past 10 days and need to be on both anti-histamine and steroid cream.

two days after bite, not showing those on arm, tight, hip, and parts rather not mention here

fourth day - one of the itchiest days (actually can't think of which day is not itchy)

day 11 - finally healing, with an accidental scratch scar

Fortunately unlike ticks in the temperate, these tropical ticks are unlikely to be vectors of diseases (e.g. Lyme disease). In every stage of their lifecycle, they just climb up a stem/grass and wait to attach to a passing host, and a meal of fresh blood. The only way to avoid getting their painful (itchy) bites is to avoid physical contact with the shrubs they perched on, or wear pesticide-treated clothes (and get some chronic poisoning at the same time).

I guess the moral of the story is not to walk into the forest if you do not need to (this goes to everyone, whether or not your favorite activity has to do with some letters 'H'). Hopefully ticks do safeguard the seedlings from some human trampling.

Myth or Truth: some people believe that ticks deposit eggs under host's skin when they bite, and the larvae will chomp away tissue after they're hatched, hence the unbearable itch. Think about this - if the ticks are able to inject eggs via their mouthpart (hypostome), they must have had their organs growing in their face, and they must be doing only "oral" sex.

Big Trees alive!

2007-05-15T21:29:00.000+08:00

Finally, I'm reviving this blog after almost two years. Mainly because the basic fieldwork of the Big Trees Survey has been completed, and I should start the momentum of writing (besides my regular botany/reading/analyses/software-learning). Also because I really want to say something about our last remaining primary forest to the masses out there.

The survey took almost 2.5 years in the 164-ha BTNR. A total of ca. 140-ha continuous, closed-canopy forest is covered with the 10,200 trees we tagged, measured, mapped, and identified. About 410 morphospecies were recorded, which includes several new records for Singapore as well as BTNR, and numerous rediscovery of extinct species. It's always rather tricky in claiming new records in plants, especially when only sterile specimens are available (herbarium normally takes only fertile specimens, of which records are officially recognised). However, almost all our new records are quite distinctive even in sterile specimens, and certainly I'll work hard to collect, deposit in herbarium, and then report. I also hope that the DNA barcoding of trees will also help me confirm the identification.

This survey is unique and significant in many ways:

It could possibly be the largest forest tree survey block (not really a plot since it's not square) in the world (one survey in Costa Rica covered 150 ha but only survey six tree species in all size classes, cf. Clark & Clark 1992)

This complete inventory of all canopy trees not only reveals the actual floristic composition and stand structure of BTNR (suggested in the many great works by Drs. R. Corlett and I. Turner), but also serves as a great tool in understanding the dynamics of a fragmented forest, through long term monitoring (most studies on forest fragments were done in Amazon on many 1-ha or smaller plots, cf. most works by Dr. W. Laurance)

The map stored in ArcGIS is useful in identifying critical areas for better management and conservation, as well as for collaborative study in the future. Scientists who wish to locate trees of any particular species can extract easily from the GIS database, e.g. Dr. Koichi Kamiya who is now studying the population genetics of Shorea.

The data will be integrated with the previous two 2-ha Forest Dynamics Plots (FDP) in BTNR, and stored in a relational database (Open Office Base). This HSQL database will then be part of the global CTFS FDP plots database (MySQL).

Having said that, still plenty of works ahead.

All BTNR trees bigger than 30 cm in diamater. Cyan dots represents all Shorea spp., one of the main indicator genera of primary forest area

Slow Poke

2005-10-07T22:44:00.000+08:00

Some fresh, recently fallen Keruing (Dipterocarpus caudatus ssp. penangianus) fruits were seen along Tiup-tiup path - almost two months after the 'end' of the mass fruting season. Well.. the determination of the timing is really quite ambiguous - nobody did actually scan through all twigs to see if there are any 'leftover'.

Anyway, these fruits are in average smaller than most typical fruits, which calyx tubes are about 2~3 cm in diameter.

Check out the seedlings from the earlier batch, already quite tall! (Late fruits are placed beside the seedling in the top-left and bottom photo for comparison)

So, what actually happened to these late fruits? Why did they fall late? Why are they smaller? Are they as viable as the earlier batch?

Can being late an effective strategy to increase survivability? Perhaps.. Or may be they are just abnormal

Hear ye, hear ye!

2005-08-12T16:47:00.000+08:00

So this tree introduction thing was supposed to be a weekly series.. but looks like we're a weeee bit too busy, what with 4/5ths of BTNR still waiting for us. But we'll still try our very best to keep posting! In fact, here's our very next tree.

Next in line of the most common trees at BTNR is the Terentang, scientifically known as Campnosperma auriculatum. "auriculatum" is a latin reference to the "ear-lobes" at the base of the leaf. If you pick up a Terentang leaf and look at the base, you'll easily see what the name means. This is how to identify a Terentang:

I personally find the easiest way is to look up at the flat-topped crown of the tree, because the Terentang leaves are arranged in a very characteristic spiral that makes it very pretty to look at.

The leaves are very easily recognisable too. They are large, up to 20cm wide and 52 cm long. The shape of the leaf is obovate, with a notched apex (a slightly heart shaped tip) and a base that is tapered and forming a pair of ear-like lobes. The leaf tapers all the way down, so there is no distinct leaf stalk. There are 12-23 pairs of secondary veins, and the tertiary veins are also easily visible on both sides of the leaf, and are a mix of ladder-like and net-like.

The tree trunk often has short spreading buttresses. It can be grey to yellow coloured, and the bark is usually shallowly-fissured, cracked, or papery scaly.

A good place to spot the Terentang is at the beginning of the main road up BT hill. There are Terentang on both sides, and if you look up, it shouldn't be hard at all to spot the spiral arrangements of the leaves.

Scaphium macropoda

2005-08-10T20:17:00.000+08:00

Cheng teng anyone? Visitors to BTNR are now treated to the sight of spilled jelly along the main road, near Kruing Hut. This jelly substance, is more often seen in our popular local dessert, Cheng Teng. The jelly substance came from the seed, after it has absorbed moisture. This jelly possibly provide nutrients to the developing embryo. Even people who purchase the seed from shops may not recognise it, dangling from its splitted open fruit pod, which resembles a boat. This boat-like design acts like a spiraling parachute, dispersing the seed some distance away from the parent tree. If you are lucky enough, you might be treated to the sight of the fruit spiraling down.

The scientific name of this tree is Scaphium macropoda, and in Malay, Kembang Semangkok. Medicinal value of S. macropoda has long been recorded in Chinese medicinal books and is said to be good for asthma, sore throat, constipation and alleviates heatiness in general.

Right now, especially after the numerous downpours last week, many young S. macropoda seedlings are sprouting out among the mess of jelly!

Ah.. I love my babies!

2005-08-03T22:00:00.000+08:00

The long flowering and fruting season (since March) is so exausting.. But now I'm so proud and happy to see many of my babies spining gracefully down the canopy.. lying on the ground and patiently wait...

For some rain water.. and for a chance to grow!

Not forgeting the babies of my cousins, Meranti Tembaga (Shorea leprosula)..

And Nemesu (Shorea pauciflora)!

Remember to keep to the trail.. NEVER try to walk into the forest and step on any of our babies! We'll be crying and screaming but you just can't hear...

Tropical Fruits in season

2005-08-02T23:23:00.000+08:00

So after months of searching & collecting, we finally got a few of our Fruits of Labour - the seasonal tropical fruits for now. Sorry, if you are thinking of the palatable Durian, Mango, Sq H2O Melon etc, too bad for we found none of those except the JackfruitS.
First pix on left shows the smaller fruits while the ones on the right are bigger - just imagine .... the "nut" of the big one on top is almost the size of the fist of Plywood, or is s/he Ploywind?
Anyway, hope you enjoy the pics. BTW these are not the full fruits of our Labour. There are still more, like ... sorry, I forgot, due to the extremely wet July. Wet weather erode my memory. Inspite of the wet weather, we still have to hug the trees. If you ever try hugging a tree when the bark is wet, pls don't take the public transport back home w/o a change of clothing, unless you are targetting for a Free stay at the infamous 5 star Wooden Bridge Hostel.
Enjoy our Fruits & tell us their names if you can.

Calling all residents of Tampines!

2005-08-01T21:50:00.000+08:00

Our tree this week should be familiar with many residents of the East of Singapore. It is the Tempinis tree, after which the estate Tampines was named. The scientific name for the Tempinis is Streblus elongatus. In Latin, Streblus means crooked while elongatus means elongated or lengthened - possibly refering to the flowers arranged in catkins (spikelike, often pendulous, inflorescence of petal-less unisexual flowers, see below).

The Tempinis is scattered about the lowland forests of the Malaysian Peninsula, as well as Sumatra. It is also one of the more common trees in Bukit Timah and the rest of Singapore, so one should have no problem finding one. To identify one, look for:

A medium sized tree, which may reach 33m height and 80cm in diameter.
The trunk is often slightly fluted (with furrows or grooves/not perfectly round).
The bark is usually smooth to dippled (bark peeled off in tiny patches, leaving some "scooped" marks), sometimes shallowly fissured, and is grey-brown in colour. Often, it will have a patchy green-white colouration due to lichens growing on the bark.

The leaves are simple, and are arranged alternately. The leaf is oblong-elliptic in shape, sized about 10~38cm x 2~8cm large, and has a stalk about 0.2cm~1.3cm long. The apex (tip of the leaf) is sharply pointed, the base is unequal, and there are about 10-20 secondary nerves which are sunken above and visible on both sides of the leaf. If you touch a leaf, the undersurface is usually rough.

Timber of Tempines is very hard, very heavy, and is one of the most durable. Scarce supplies, however, means that use of Tempinis timber is limited to small articles such as tool handles in which both toughness and flexibility is needed.

The tree is all throughout Bukit Timah Nature Reserve, and there are many along the main road. Tampines residents should definitely go check this tree out!

five long wings

2005-07-20T00:27:00.000+08:00

Thought you have seen it all? 3 long + 2 short wings, 2 long + 3 really short ones, 4 long ones...etc. So who is this with 5 long wings? Well, it is something from plywind's Siam trip. Easy to guess huh =) Notice the resin exuded from the tip of the nut?

Shorea parvifolia

2005-07-19T22:48:00.000+08:00

Aaaaaaah! Finally, we got the mysterious one - Shorea parvifolia (Meranti Sarang Punai). We were wondering why during this masting period, when all Dipterocarpaceae are fruiting .... this parvi, that parvi, all not flowering & fruiting! Why??

Finally, Bluebird nailed one tree deep in the Jungle Fall Valley and confirmed by his very good Nikon bino.

Sorry Plywind, you missed it. We will show you the location if you treat us to a nice lunch of BIG prawn noodles across from BTNR.

Hope you all enjoy the pics, it may be another 8 years before you see another one of these mysterious fruits. Really beautiful with 3 very long wings.

shorcu shorcu everywhere...

2005-06-25T20:20:00.000+08:00

We begin a new weekly series to keep our blog happily active, featuring none other than our big trees!

To kick off our series, we introduce Shorea curtisii, otherwise commonly known as Seraya. Yep, that's the Shorcu that was talking to you in this blog's inaugural post on April 1st. SHORCU is our short code for the tree's full name. If you're taking a walk in the trails on a weekday and hear someone shout "SHORCU!", that's us at work in the reserve, identifying a Shorea curtisii.

We're about one-fifth our way through the Bukit Timah Nature Reserve, and already, the Seraya tops our list as one of the most abundant species at the reserve. The species is distributed on Hill Dipterocarp Forest throughout the Malay Peninsula, from Thailand to Singapore. In Bukit Timah Nature Reserve, the tree is very common throughout, and very particularly so along Jungle Fall path off from the Main road.

The Seraya is a majestic tree that is relatively easy to identify. To spot this common tree, look for the following characteristics:

They are large trees, easily over 30cm in diameter, and we have measured many reaching over 100 cm in diameter.

Their trunks are usually well-shaped and round, can be grey or reddish-brown, and are characteristically coarsely-fissured, though this may not be so obvious in younger trees (picture akan datang).

The tree crown is light-coloured and appears greyish-green (Due to the fact that the underside of the leaves are mostly glaucous - see below) . The leaves also grow in small clusters on the branches, and dangling down like small umbrellas.

Their leaves are hairless and smooth. They are normally lanceolate (lance-shaped) or elliptic, acuminate (with an acute tip), and about 10cm by 4cm in size (leaves are bigger on younger/lower branches or on young trees). Leaves on higher branches of a mature big tree usually have their upper surface covered with a glaucous bloom while their lower surface pale silvery or yellow glaucescent (not so glacous) - giving it a distinct greyish-blue appearance on the canopy.The leaf stalk is slender and about 2.5cm long, and is often bent in leaves that have dropped. The primary and secondary nerves are clearly visible. There are about 10-18 secondary nerves, roughly parallel but curving upwards to the tip at the leaf blade. The tertiary nerves are fainter but still visible, and are ladder-like. (to understand these it's better to have some leaves in your hands :p)
Flowers are small, about 1.5cm across, with 5 petals and 15 stamens, white to pale yellow in colour. (You don't see them every year... And when they fall it's like snowing in the forest!)

The fruits are winged, like a shuttlecock. There are 3 large wings and 2 short wings, surrounding the nut, the entire fruit about 6 cm from wing tip to nut when ripe. The wings turn red even before ripening. The Shoreas in the reserve are currently fruiting, and their fruits can be seen scattered liberally all over the reserve. This happens very rarely, about once every 5-10 years, so do come down to check our the Shoreas' winged fruits!

Other interesting facts about the Seraya:

Seraya has many other relatives in our reserve, for example Meranti Tembaga (Shorea leprosula), Melantai (Shorea macroptera), Nemesu (Shorea pauciflora) and Meranti Sarang Punai (Shorea parvifolia) . These Shoreas belong to the group of Red Meranti, Their woods are light-weight, durable and highly valued! (Seraya's wood is suitable for making furniture, interior finishing, flooring, panelling, doors and veneers)
Being one of the tallest trees on Bukit Timah, Seraya often fall victim to thunderstorm and lightnings! You may see some big fallen Serayas along the main road to summit :'(
Their growth-form can be so variable that people mistaken them for other species (which is true for many kind of Shorea..) Like this "Shorea bracteolata" here...

Have fun looking out for the Seraya... Being the most common tree around, it shouldn't be too tough to find! ;)

Horny-bill

2005-05-04T23:00:00.000+08:00

Finally.. we saw the elusive Rhinoceros Hornbill, Buceros rhinoceros, near Fern Valley! First feeding happily on some climbing figs (may be Ficus aurantiacea), then got chased away by some Greater Racquet-tailed Drongo.. Haha.. Despite the constant pestering by drongos, it seems quite happy living in the Fern Valley - may be due to the abundance of food :)

Nobody knows from where it came from. For sure it's not native, simply because Singapore doesn't have any Rhinoceros Hornbill in the wild. Well.. we believe it could be an escapee from someone's house.. someone who smuggled it into Singapore from either Peninsular Malaysia, Borneo, Sumatra or Java..

All the best hornbill! Too bad it can't be really horny by being alone in this forest *grinz*

Rains of Flowers

2005-04-30T01:19:00.000+08:00

It has all in all, been a fruitful field week, and we have been blessed with showers... not of the water sort... but of flowers! Especially now that SHORCU, the most abundant Shorea is also flowering, ed, bluebird and plywind are quickly adorned with nature's pretties, once they step into the forest. Yet for those of you familiar with SHORCU's flowers, you will soon notice that it is conspicuously missing from the picture above. as the tiny flowers are not for amateur photographer like ply.

Yup, this being the mass flowering period, flowers are everywhere to be seen in the forests. Still, not everyone is appreciative of this rare display of Mother Nature. Majority of the throng at BTNR still stomp through the forest, without seeing much. What a pity!

Well, after much has been said about mass flowering, just what is so special about this, that makes many of us nature lovers go gag gag over? And what triggers this phenomenon? Some thing to chew over this long weekend ;)

We are not alone!

2005-04-17T23:00:00.000+08:00

This blog is too empty, I thought. What to do? The trees are just too many for Plywind and Bluebird.. Sigh.. We hope we can have 48 hours a day.. or a helicopter to help us accessing the canopy!

Nevertheless, our work is still very exciting! Not only the magnificent trees, but also some surprise encounters you might get.. day-in, day-out.

A common sun skink, Mabuya multifasciata, just at the Visitor Center. It is usually seen basking under the sun along most forest trails.
(Pic by plywind, at BTNR Visitor Center, 17-03-2005)

Juvenile of a Malayan giant frog, Linnonectes blythii, sighted at the pool along Cave Path. This is one of the largest frogs in Southeast Asia - able to grow up to 18cm long. The adults feed on a variety of large prey including crabs and even frogs!
(Pic by bluebird, at Cave Path pool, 30-03-2005)

This colugo, Cynocephalus variegatus, was resting (sleeping?) on this Magnolia elegans when it was approached and disturbed (by us, the tree-huggers!). Flabbergasted, it quickly climbed up the tree into the canopy. My previous colugo sighting (at Ken's reforestation plot - behind South View Hut) was more than a little surprise - a gliding performance!
(Pic by bluebird, at Fern Valley beside Quarry Road, 13-04-2005)

Juvenile of a Wagler's pit-viper, Tropidolaemus wagleri. Venomous, but unlikely to cause death, this beautiful snake can grow up to 1 meter and turn darker when it's grown up.
(Pic by plywind, at Rock Path-Catchment Path? 16-03-2005)

Cute! This juvenile spiny hill terrapin, Heosemys spinosa, will lose its 'spines' on shell when it's grown. Its colour matches the leaf litter on forest ground, perfectly. Needing such a wonderful camouflage (for protection), I wonder what animal would eat this dangerous-looking creature with spiny-shell! (but I still think it is cute, though!)
(Pic by plywind, at Rock Path-Catchment Path? 17-03-2005)

It's the season of mass-flowering!

2005-04-04T00:36:00.000+08:00

Intriguing big-small flowers of Keruing (Dipterocarpus caudatus spp. penangianus): Are there many Dipterocarpus species on Bukit Timah or are there just many variety of one species?

Tree-fool

2005-04-01T23:00:00.000+08:00

Some researchers, with the Centre for Tropical Forest Science (CTFS), are now working on the big trees at Bukit Timah Nature Reserve (BTNR). Within one year (hopefully!), all trees with diameter at breast height (dbh) of 30cm and above in the 164 hectare Reserve are to be identified, measured, tagged and mapped. Working for 3-4 days a week in the forest, these people (basically just two) are walking across almost every inch of BTNR (and of course, bashing through many irritating rattan-laden patches and some relatively untouched slopes/valleys!). They are here to share with you what they have learnt about the big trees that form the main structure of the forest on Bukit Timah and also some interesting flora and fauna they encountered along the way!

By the way, this is just one of the Seraya (Shorea curtisii) on the hill.. They (human) say my species is the most prominent one at Bukit Timah but I never know the exact number of my own kind around me :p Well.. may be next year when the project is completed. Meanwhile.. just stay tuned and see what these people say about us, the BIG TREES!