Plant Characteristics
Structure
The forest plants are arranged in 5 layers.
Emergent layer: the top layer consists of trees of up to 50metres. These trees are usually far apart from one another. They have buttress roots to provide sufficient support.
Canopy layer: the middle layer consists of canopy trees, with ferns and non-parasitic plants such as lianas and epiphytes. The trees grow to a height of about 20 to 30 metres and form a continuous canopy.
Understorey layer: plants growing in this region mainly consist of small trees with narrow crowns, herbs etc. The layer is about 15 metres in height. These young trees will strive for sunlight and most of them will replace the taller ones.
Shrub layer: as the name suggests, shrubs, ferns, bushes, herbs etc. are found. They grow to about 5 metres.
Ground layer: there is little undergrowth on the ground. Few plants such as ferns, saprophytes and shady plants can be found. The reason is that the crowns of the tall trees block out the sunlight and very little of it reaches the ground. However, when sunlight falls on a clearing, undergrowth will be intensive around that particular area. Small trees, shrubs and lalang will grow and make the area into a belukar, or secondary forest.
Roots
The fertile topsoil of the Amazon forest is usually shallow, not more than a few inches of soil above reddish clay. As a result, the roots of trees stretch over the surface instead of burrowing deep underground. In order to suit the situation, trees develop buttress roots and organic flanges. These adaptations grow out from the base of the trees in all directions to provide sufficient support. The buttress roots allow the trees to absorb more nutrients from a greater surface area as many rootlets of the buttress roots extend downwards from the bottom of the roots.
In flooded parts or the mangroves, trees are exposed to the water currents. Stilt roots can be found emerging from the main trunk 1 to 2 metres above the ground and extend to the soil. This feature helps to provide support to trees against water currents.
Leaves
The leaves of the trees are broad and dark green in colour to meet the rapid speed of transpiration due to the hot climate. The leaves are thick and leathery so as to withstand heat.
Drip tips
Most leaves of trees have drip tips, a pointed tip at the end of the leaves. This helps to drain away the excess rainwater from the leaf. The Amazon Forest is located at the equator where thunderstorms are common. The drip tips ensure that the leaves do not break due to the weight of water that is accumulated on the leaves. Besides, the drip tips minimize moisture the leaves retain and prevent insects or parasites eating the leaves.