Question 1 Explain the various layers of vegetation in a forest ?
The Structure of a Forest
The five layers of a forest vegetation starting from top and going down are : Canopy, Understorey, Shrub layer, Herb layer and Forest floor.
The amount of sunlight available in each layer of the forest decides which type of plants grow and survive there.
The uppermost branches and leaves of tall trees which act like a roof over the forest ground is called canopy. The canopy is more or less a continuous layer of leaves. It is the upper part of the crowns of tall trees in the forest which make up the canopy.
The canopy is filled by leaves from large, mature trees. Canopy leaves intercept the sunlight available to the forest. Less than 50 percent of the total sunlight falling on the top of forest can pass through canopy and go down to the plants in forest layers below the canopy. The canopy of forest is full of various type of animals and includes insects, birds, reptiles, mammals (monkeys, etc.), and many more.
The layer of vegetation in a forest which is just below the canopy is called understorey. The understorey layer consists of smaller trees and tree saplings. The understorey layer of forest has comparatively much less sunlight.
The smaller trees found in the understorey grow to become bigger trees only when tall trees die and open gaps in the canopy.
(3) Shrub Layer
The layer of vegetation in a forest which is just below the understorey, is called shrub layer. The shrub layer consists mainly of mature shrubs and bushes. The shrub layer has a smaller vegetation which is between 1 metre and 2 metres in height from the forest floor. Many of the shrubs in the forest depend on animals for the dispersal of their seeds. There is not much sunlight in the shrub layer.
(4) Herb Layer
The layer of vegetation in the forest which is just below the shrub layer is called the herb layer. The herb layer consists mainly of herbs, ferns and grasses. The herb layer is the lowest layer of vegetation in the forest (having leafy plants).
Very little sunlight remains for the plants in the herb layer. In the herb layer, the plants grow and flower early in the season so as to get sufficient sunlight before the canopy leaves open and obstruct sunlight.
(5) Forest Floor
The ground surface of forest is called forest floor.The forest floor has many kinds of small leafless plants such as mosses, liverworts and lichens, etc. The largest animals in the forest live on the forest floor. The forest floor has also many kinds of insects and worms.
The decomposer organisms such as bacteria, and fungi are also present on the forest floor. The forest floor is covered with dead and decaying plant matter, decaying animal matter and animal wastes.