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Official Magazine of the Nature Society (Singapore)
Awakening to
MacRitchie's Forest Riches

The riches of this forest are many. Some see only the beauty of the birds and trees, but the forest floor, its leaf litter, also teem with life. Take a walk with Goh Si Guim and see the depth of the forest's worth. All photos by the author unless otherwise stated.

Calm reigns over the waters
of MacRitchie Reservoir
at the break of dawn
As dawn brightened the sky one April morning, a perfect reflection of the forest formed on the calm waters of MacRitchie Reservoir. The occasional bubbles and ripples, created by turtles and fish surfacing for air, added mystique to this almost primeval setting. At first the forest seemed to be in a trance, but as the morning light filtered into the forest, the momentum of life began to pick up: the first sounds came from a chorus of forest songsters.

From their perches high on the Tembusu tree, the resident Collared Kingfishers uttered barrages of shrill staccato 'laughs'. Moments later, a pair of Hill Mynas appeared, their yellow head wattles glowing brilliantly in the first rays of the morning sun. The piercingly loud but melodious whistles of the mynas are more pleasant to the human ear than the kingfishers' calls.

It is now bath-time for a White-throated Kingfisher. I watched as it splashed repeatedly into the water. After each splash it would return to its perch, fluff its feathers and preen them. Then, from somewhere amongst the trees, came the unmistakable loud cries of the colourful Banded Woodpecker. In the background was the incessant 'whine' of the cicadas.

Back to the water's edge, and I spotted a Yellow Wagtail pacing the muddy bank, its wagging tail revealing flashes of its yellow vent. Numerous pond skaters were sliding back and forth on the surface, creating countless ripples. Near the far bank, a monitor lizard was propelling itself through the shallow water, sensing for food by flickering its tongue in the air. Small butterflies like the Branded Imperial, Common Grass Yellow and dragonflies were fluttering over small bushes...

Further inland, Sun Skinks would sometimes lie motionless by the side of the trail but, when approached too closely, would dash away blending in with the leaf litter. Later in the day, I discovered one rummaging under the leaf litter, looking for food. On another occasion, I saw young monitor lizards, also foraging for food amid the leaf litter.

Flying Lizards are more active. They glide swiftly, flashing their menacing yellow throat "blade", as they move from tree to tree. On another walk in the MacRitchie forest, some rustling in the resam thicket stopped me m my tracks. I waited expectantly, wondering what would present itself. It turned out to be a native Spiny Hill Terrapin. This little animal paused, then raised its head to sniff the air. Sensing no danger, and ignoring my presence, it trudged across the path slowly on its stumpy legs.

The fluttering Branded Imperial
is a delightful distraction in
the forest. It is shown here on
its caterpillar foodplant,
the Smilax vine.

Common Sun Skinks
are often encountered along
forest trails or they can be
heard scurrying away
as you approach

Flying lizards glide from
tree to tree with wing flaps
on the sides of their bodies.
This male displays his yellow
throat flap from his perch.
Photo by Phang Tuck Phew

A flush of tender
new leaves
add colour to the
monotone of green
Colour from the tender leaves
The forest is not always a monotone of green. Flushes of new growth, flowering and fruiting plants add a splash of colour here and there. Some young leaves are intensely purplish red. Tender and succulent, they are much favoured by caterpillars. Other insects that feed on young leaves are white frilly scale insects, also known as mealy bugs. These creatures use their hypodermic-like stylet to penetrate into and draw nutritious sap from the soft plant tissue. Mealy bugs have a symbiotic relationship with ants. Honeydew excrement exuded by the mealy bugs are collected by the ants to feed their larvae. In return, the ants tend and even protect them. As the leaves mature, they gradually turn green and become tough.
I see a splash of orange and it is the wild Ixora bearing clusters of tiny light-orange flowers at the apex of its branches.

More spectacular are the white, fragrant and large trumpet-shaped flowers of the treelet, Rothmannia macrophylla. This plant flowers infrequently so one is lucky to come across it in bloom.

Look under some large leaves and you may see the numerous attractive but inconspicuous flowers of the Thottea grandiflora. Each flower of this small plant has a distinctive purplish-brown lampshade-like perianth, with pale netting-like veins. It exudes a faint unpleasant odour.

Another visit, three weeks later, and I found fruits in place of flowers. The Ixora bears berries while the Thottea bears slim okra-like pods.

Quite unexpected was the discovery of the fruit pods of the Sterculia, borne in sets of four and hanging like chandeliers. I must have missed the flowers on the previous walk, but this time the bright orange-red opened elliptical pods did not escape my attention. They were not yet opened in the cool of the morning.

Walking back later in the day, I saw that one pod had dehisced, revealing several jet-black seeds attached along the rim.

The crowded and brightly
coloured inflorescences of
Ixora adds much needed
colour to the forest

The most distinctive feature of
the flower of Thottea grandiflora
is its three-lobed campanulate
or bell- shaped perianth.
It is a relative of the Aristolochia
vine and is a caterpillar foodplant
for two locally rare butterflies.

The ripened pods of Sterculia
are strikingly red and stand out
amongst the greenery
Fruiting trees always attract a host of frugivorous animals. The resident troop of Long-tailed Macaque monkeys was up, engaged in their routine of grooming themselves and each other, and foraging in the branches overhead and on the ground. In their wake was a Greater Racket-tailed Drongo, picking off insects disturbed by the monkeys. Two species of squirrels, the Red-bellied and the Slender, having converged on the same tree, were engaged in raucous territorial conflict. However, on the same tree, the Asian Glossy Starling and the Pink-necked Green Pigeon were feeding peacefully, displaying nonchalance at the dispute among the rodents.

Flowering and fruiting trees are beacons for animals such as bees, butterflies, moths, birds and bats in the forest. They play important and varied roles as pollinators of the flowers and dispersal agents of seeds. The forest provides and the favours are returned, a crucial and mutually beneficial relationship that ensures the perpetuation of species.

Riches in the Leaf Litter
What most of us do not appreciate as we crunch our way over the abundant plant litter on the forest floor is that it acts as ground cover, preventing loss of vital topsoil during torrential rain. More than this, the dead and decaying leaves represent a huge store of nutrients just waiting to be unlocked.
A key agent for releasing this resource are the termites. Some species have bacteria in their gut that aid in the digestion of the tough woody material while others carry the material back to their nest where they are used to cultivate fungal gardens. One large swarm I encountered were working their jaws into the forest litter, guarded by aggressive soldiers. The mechanical crunch was audible when I placed my ears close to the ground.

Many other tiny unseen animals, including millions of insects and their larvae, also contribute to the recycling and life-giving process. Fungi permeates many aspects of the forest, silently breaking down these indigestible substances. Almost everything is efficiently re-utilised by the plants in the forest.

Termites are efficient and
indispensable workhorses
of the forest nutrient
recycling process

This colourful mushroom
curiously pushed itself
through the leaf litter
Yes, the forest is a intricate green tapestry made up of a multitude of lifeforms interwoven in a complex way To uncover and truly appreciate Nature's splendour, tune into the gentle soothing rhythm of life in the forest. You will be amazed by each discovery. Do not hurry. Nature never reveals her secrets all at once.

Note: Forests are precious ... and so fragile. As soon as trees are cut down and the forest floor laid bare, it takes only one season of monsoonal rain to divest the once-lush forest of its life-giving topsoil.

Goh Si Guim is a Perfusionist (providing life support during Open-heart Surgery) with the Cardiac Department, National University Hospital. He is an active member volunteer of NSS, being an exco member as well as leading nature walks.

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