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THE FOREST

THE FOREST

This Jungle preserves a perfect example of undisturbed tropical rain forest, which is most rich in species and most complex in structure. A multi-layered: The dominant trees tall - unbranched trunks almost cylindrical, 'stand head and shoulder' above the rest of the forest. Sometimes they stand-alone. Sometimes they form a solid canopy with crowns touching. Families of Diptrocarpaceae are usually dominants. Tualang tree (Kompassia Excelsa - Leguminosae) is an excellent example of a dominant.

Beneath are many smaller trees, either young dominants striving to reach the light or shade-tolerant species, which do not have capacity to join the upper canopy. Dominants have spreading rather flat crowns; under storey trees have tall narrow crowns. Ground vegetation must survive in deep shade and faces severe competition for nutrients from the roots of the trees above. Hence in virgin rain forest the ground flora is not especially dense and comprises many palms, as well as seedling and saplings of trees with relatively few herbs or small shrubs. The exception is along the river where light is available and undergrowth is extremely dense.

An evergreen: Because there are no seasons in the tropics there is no dormant period - trees may grow all year round> All of the trees do change their leaves but many do so progressively, so that they are never bare. Those that do become bare do so only for a short time and not necessarily all at the same time. February to April is the dry season and there is much color in the forest at this time as a scattering of trees loses their old leaves and sprouts new ones.

Immensely rich in species: Raptly there are over 240 different species of trees in a single hectare considering trees above 10 cm diameter alone.

Temperate forests commonly comprise only a few different trees species on any one area. Not surprisingly the density of occurrence of any given tree species is very low.

Incredibly old: It is 130 million years old! While other parts of the worlds were subjected to the destructive forces of extending ice caps, fluctuating sea levels and changing climates during glacial epochs' what is now the Malay Peninsular was unaffected. In consequence these forests have been a focus of plant (and animal) evolution for longer than any other forests of the world.

Unique adaptations: Buttresses - These are outgrowths confined to the lower part of trunk. They arise through secondary growth along the upper side of lateral roots and may extend well up or far out from the trunk of the tree. Large trees of the rain forest tend to have shallow, spreading root systems, rather than tap-roots. Buttresses are most common on large trees. Thus buttresses are assumed to help support the tree. But by no means all-large shallow-rooted trees have buttresses and buttressed trees blow over in the wind just often as un-buttressed ones.

Stilt roots - These are stout woody roots, which emerge above ground from the main trunk and arch downwards into the soil. They are found more often in undestroyed trees than in dominants and are most common on-trees growing in swampy conditions.

Brightly colored young leaves - The best example is the Kasai tree (Pometia Pinnata) with large pinnate leaves, bright red when new. But it is a common feature of many forest trees, and some palms also. Not only are these leaves brightly colors, but they often hang very limp as if wilting. Only some days later as they become green, do they stiffen and attain a normal position. Various experiments have been done on colored and limp leaves, but nobody has come up with a satisfactory answer as to why nature should work this way.

Climbers - Climbing plants, especially the large woody lianas, occur in far greater abundance in tropical rain forest than elsewhere. Climbers are light-seekers, and are thickest along riverbanks. Inside the forest, it is the thick lianas twisting up on the treetops that attract attention. Main stems of these climbers are usually un-branched, but ones the upper canopy is reached the stem branches extensively into a large leafy crown. The Rattans are a large group of climbing palms painfully obvious to any jungle traveler due to the sharp reflexes thorns on their leaf stems. The leaf part climbs to the light by means of these hooks, with the man stem sometimes growing to more than 61 meters long. (From these Rotan's, cane or rattan furniture is made.)

Epiphytes - These are plants of small size bur generally having high light demands. They survive in the tropical rainforest by growing on the trunks and branches of trees. A common epiphytic fern is a Bird- nest Fern (Asplenium Nidus), with large pale, strap-sharp leaves. Epiphytes depend on their 'host' for support only. To gather their nutrients and water supply, they rely on 'soil' from broken down organic matter e.g. fallen leaves, which they slowly collect around their roots. Many orchids are epiphytic and these and other epiphytes can be seen hanging around.

Stranglers - The strangling fig is the best example of these remarkable trees. Figs are eaten by birds and animals and the seed deposited on the branches of forest trees. The new plant starts life as an epiphyte but sends a root down to the ground beside the tree trunk. As the plant grows and spreads, so the aerial roots (now based in soil) branch and rejoin, surrounding the tree trunk. These roots thicken, until the tree is enclosed in a web of vine-like roots. Principally through construction, the host tree ultimately dies and then rots away leaving the now-substantial crown of the fig supported on a 'trunk' of tightly interwoven roots.

Decomposition in the forest:

Tropical Rainforest plants obtain their nutrients in several ways. These include from rainfall, from the soil and from decaying leaves at the soil surface. The main source of nutrients is the decomposition of dead plant materials of the forest itself. Dead plants materials found on the forest floor are often referred to as forest liter.

Although the layer of forest litter is generally thin, it is maintained by continuous litter fall from the forest, various species of Shores sp. and Kompassia sp. that make up the main canopy of the forest are responsible for most of the forest litter. The decomposition process in the rainforest occurs very rapidly. It releases organic acids that speed up the formation of soil. This soil then serves as another nutrient source for plants in the rainforest. These process show that important role forest litter plays in the rainforest. It is so important scientists to determine the rate of decomposition in the forest sometimes measure that litter fall. A high rate of decomposition is characteristic of a productive forest. These are other vital members of the decomposition process who work quietly in the background - termites, ants and other insects. The termites remove all wood matter of a tree trunk except the outer layer, which provides them with shelter and protection. Termites also contribute to the production of soil. The walking around here will highlight some of the decomposition processes in the lowland forest and introduce you to their various players.

Forest Litter:

Forest litter describes fallen trunks, leaves, twigs, branches, fruits, seeds etc. Notice the large amount of forest litter here. Fungi (the plural for fungus) usually thrive in places with forest litter. These appear mostly as mushrooms and toadstools. They obtain nutrients from dead plant materials. Many of them are poisonous but some are eaten.

Termites:

There are over 2,300 species of termites in the world, of which about 200 species are found in Malaysia. Most termites feed on dead plant material although a few species are known to attack living plants. Termites are important members of the rainforest community.

They consume large quantities of dead organic matter and this improves conditions for other microorganisms to grow, which hastens decomposition in the forest. Being so numerous, they are also an important food source for other animals like Pangolins, Malay Civets, Lizards, Frogs, Snakes, Squirrels and Bears.

Termites live in colonies in a highly organized social structure. At the heart of each colony is a fertile female (the queen), accompanied throughout her life by a fertile male (the king). They are capable of producing hundreds and in certain species thousands of eggs per day. The larvae have the potential to develop into adults of three castes; workers, soldiers and reproductive. The workers are responsible for construction of the nest, gathering food and tending the eggs and larvae. The soldiers defend the colony if attacked. Only the reproductive castes develop wing. This termite's fly from the nest to seek partners and from their own colony.

Termite Mound:

Most termites build their nests above the ground. This is the nest of a particular species that feeds on leaf and wood fragments. Although its nest is obvious, the termite is rarely seen because the workers forage for food underground. The Microcerotermes Dubius species is known to attack live trees.

Forest Fact and Figure:

Malaysia's Green Vision - Maintaining high percentage of land area under natural forest and tree plantation based on a long record of progressive forest management.

Land Area Under Forest And Woodland

Countries

Percent Of Forests And Woodland to Total Land Area

Malaysia

* 75 %

Australia

14 %

Bel - Lux

21 %

Canada

39 %

France

27 %

Germany

30 %

Netherlands

9 %

Switzerland

28 %

United Kingdom

10 %

United States

31 %

Source: FAO Production Yearbook,1993

* Latest estimate


Layers of the forest

The trees in the rainforests grow to form different layers. There are usually four layers.
There are three main tree layers and a shrub layers.
These layers enable many different animals and plants to live in a small area.

EMERGENT LAYER
This layer is the highest layer. It is made up of the tops of the tallest trees.
The tops of these trees look like umbrellas covering the other trees. This layer remained a mystery until more recently, when researchers built towers and aerial walkways in the trees.
In these trees birds, butterflies and small monkeys live with bats, snakes and bugs.

CANOPY
Most of the trees grow up to about 25 - 35 metres tall. The tops of the trees group to form a ceiling called a canopy. Only a few taller trees push past this ceiling to make the emergent layer.
The treetops stop a lot of the light from entering the forest.
The canopy is important as it protects the soil from erosion by the heavy rains.
The canopy is the home to birds, monkeys, frogs, and sloths, as well as lizards, snakes and many insects.

UNDERSTORY
This layer is made up of trees that are growing up to reach the canopy. They stop just below the canopy and wait until a gap appears which they can then grow into.
The trees are small with thin trunks. The trees here are about 20 metres tall.
This layer is the home to birds, butterflies, frogs and snakes.

FOREST FLOOR
The forest floor is very dark. This is due to the trees above stopping the sunlight from entering the forest. It is estimated that only 2% of the sunlight actually reaches the floor.
The soil on the floor is covered in a layer of leaves, twigs and dead plants, which rot down quickly to provide nutrients for the plants.
The leaf litter is alive with invertebrates and microorganisms, which quickly rot down this surface layer. Mosses and ferns grow on the forest floor where it is warm, damp and shady.
The soil is very sandy with only a thin layer of rotting vegetation. Without the trees, the soil quickly loses its ability to support plants and turns to desert-like conditions.
The forest floor is home to some of the larger animals of the forest such as tigers and elephants.