Tuesday, July 28, 2009

A walk on the wild side: Woodcutter's Trail

This trail gets my top vote for the wildest trail in Singapore. You will be hard pressed to find anyone else save for the rare cyclist or SAF personnel. The trail proper is almost free of the trappings of civilisation e.g. board walk, stone paved paths that make the other natural areas too tame in comparison (but see below for other less desirable signs of civilisation). Nature aside, this trail has strategic significance as it cuts east-west through the central catchment from Bukit Timah to Upper Thomson. It is certainly of interest to those who want to avoid detection and movement on the main roads. (Any Mas Selamat wannabe out there?)

The old standby never lets you down
One reason for its obscurity is it is so ******* hard to find. Despite having been here before (4 years back?), I still got lost initially with its many criss-crossing trails at the Bukit Timah end. Back tracking became routine in no time. Sorry, my GPS was down and it probably would not have penetrated the forest cover for the minimum 3 satellite signals. Dear readers, do not ever leave home without your trusty map and compass, with or without GPS. After all, the compass has no batteries to fail, no parts sensitive to hard knocks and is cheap to boot. Heck, you should bring an extra compass like I did for level 1 premium insurance. And yes, it really saved the day for me.

Figures (L-R, T-B): My faithful companion; Opps, wrong turn; No surprise, this whole area is a water catchment that drains into our central catchment reservoirs; important land mark to turn into the right path!

A trail of streams
If you are waiting for a lively description of my water quality monitoring work on this trip, there is none. This was supposed to be a recce. (who knows what has changed in a span of 4 years?) More importantly, the trail itself took 3 hours to traverse. The trail's entrace and exit are not exactly next to the main road. Factoring these details in can easily add up to 4 hours or more. Did I mention that you may get lost too? Mounting a water quality monitoring operation will need good planning and lots of margin for error.

Nevertheless, the trail is crossed by several genuine forest streams. You probably can find some of the rare endemic freshwater species here though I did not try searching. Mercifully, some kind soul has set up planks, ropes or even just flower pots for easy crossing of these streams.

Your textbook secondary forest
This is no doubt a true blue secondary forest. Simpoh Air rule supreme at the Bukit Timah end, so much so that you find yourself trudging through a Simpoh Air forest.

Many forest gaps were encountered. And usually, ferns (Bracken, Resam) dominate. (Many factors could have created these gaps e.g. fallen trees, human activity.) Of course, we saw the usual Smilax and Hairy Clidemia every few paces or so.

Side note: many consider Hairy Clidemia to be a vicious weed. Perhaps. But do you know that it can stop bleeding? If you are spilling blood and out of first aid, you will be wise to recognise this plant and make it your best friend. I have tried it on leech bites and it worked! A 3-hour trickle turned into a half-hour trickle. (This is not Panadol Flu Max so do not expect instant relief!)

Figures (L-R, T-B): A sea of ferns; Hairy Clidemia; the forest floor is not dark and bare, instead it is often colonised by ferns; a large clearing in the secondary forest; fallen logs could have opened up gaps in the forest; Simpoh Air forest

The good, the bad and the ugly
In case you are hoping to find a pristine wonderland here, can it. The fact that the trail is so well marked means that it is regularly maintained and used. Vegetation was cleared by machete as seen in the slashed branches along the trail. The heavy duty ones e.g. fallen logs were cleared by chainsaw. This is all and well with me since it makes the journey more pleasant without having to bush whack our way through.
On the down side, LITTER rears its ugly head whenever you have people coming in. Perhaps not surprisingly, most litter are SAF combat rations and other issue items e.g. cylum sticks, solid fuel (we found a pack of 3 unused ones), gloves. SAF should seriously consider including environmental education as part of their soldiers' training.

At Bukit Timah end, we came across lots of evidence of the old kampongs previously there. Zinc roofing sheets, clay pots and even an abandoned cabless pickup truck. (We even found the number plate hanging from its rusty rivets. Die-hard gamblers may approach me for the 4 digit number.)
Figures (L-R, T-B): SAF tactical marking; Nparks DOES come in here - a tree tagged by Nparks; a fallen log cleanly cut up by chainsaw; SAF paraphernalia (read LITTER); clay pots everywhere; end of the trail

Thursday, July 23, 2009

Crocs in Singapore

When I was younger, I have always been skeptical of the presence of crocs in Singapore. But in recent times, sightings of these ancient creatures have been surfacing. Here is the latest documentation with a cool pic of the beast at Sungei Buloh in Biodiversity Singapore blog.

(from Biodiversity Singapore)

Widely used antifouling biocide lingers in freshwater ecosystems

via ES&T Online News on 7/22/09

A growing body of evidence shows that Irgarol and other biocides present a toxic threat to vulnerable freshwater organisms.


A biocide called Irgarol, used worldwide to prevent the buildup of algae and other organisms on the undersides of boats, accumulates and can be toxic to nontarget aquatic plants in freshwater ecosystems, a new study in ES&T has found (2009, DOI 10.1021/es900595u). Researchers are learning that the substance persists in sediments and other organic matter and can have a ripple effect throughout freshwater ecosystems.

Irgarol works by inhibiting photosynthesis. One of the main ways that this and other biocides are introduced into the water is by leaching from the paints used on ship hulls; these paints include a biocide to prevent the buildup of algae and the subsequent attachment of mollusks, a process known as fouling. (Hull fouling increases drag on the vessels, thereby increasing fuel and maintenance costs.) Irgarol is also used as a preservative in building materials and wall paints and as a biocide in power plant cooling systems.

My thoughts:

  1. Nothing new here - another chemical dispersing into the environment and causing undesired effects on the ecosystem.
  2. Question - are toxicity studies actually done for this chemical before its introduction to the market? If yes, how extensive are they in terms of the run time and variety of organisms tested?
  3. Question - why does it take so long for its adverse effects to be investigated? According to the article, Irgarol started to be widely used in the 1980s but this study only comes out now.
  4. According to the author, Irgarol is more damaging to freshwater aquatic plants compared to coastal aquatic plants because freshwater plants have a smaller range of tolerance to changes in the environment. I am not sure I agree with this. Marine organisms such as seagrasses, coral and plankton are pretty sensitive too. More research should be done as there are many more ocean going vessels using anti-fouling agents.
on the vessels, thereby increasing fuel and maintenance costs.) Irgarol is also used as a preservative in building materials and wall paints and as a biocide in power plant cooling systems.

Thursday, July 02, 2009

Reminiscing Chek Jawa (2004)

Chek Jawa can't seem to get out of my head after my visit last Saturday so I flipped through my ancient photographs of the place.

Guess what? The same iconic tree was there in 2004 but compare it to what it looks like now... what has happened in the intervening 5 years?!? Does the tree (and the surrounding substrate) look barer now or what? Too much impact from visitors? Deteriorating water quality? Or is the tree simply going through old age?

I also found some of my favourite photos - sunrise at Chek Jawa on a clear morning. Check out how the fascinating egg yolk rose out of the sea.

Figures (L-R, T-B):
The lonesome one now; the lonesome one in its splendour (2004);
These 4 photos captured the progress of a sunrise at Chek Jawa (2004)