VPE 511: Environment and Environmental Hygiene (2+1)

FOREST ECOSYSTEM

• Forest ecosystem is dominated by trees. Forests are natural plant communities. They are found in the region where there is moderate to high rainfall. They are the climax communities occupying 19% of the total land area in India. There are different types of forests depending upon the climate. They are as follows:

• Tropical rain forests: They are evergreen forests found occurring near the equator. They get high temperature, high humidity and heavy rainfall. These forests are famous for richest biodiversity. There are three layers, namely topmost layer of tallest trees. (e.g,. Lianes and orchids), shrub layer (many shrubs) and ground layer (herbs) eg., The silent valley in Kerala.
• Tropical deciduous forests: They are found a little away from the equator . There is a warm climate throughout the year. Monsoon rainfall occurs during the monsoon seasons. Since drought prevails in the forest during most part of the year, the leaves fall down during dry season.
• Tropical scrub forests: In this type of forest, dry season is longer. So, deciduous and armed shrubs and trees grow here.
• Temperate rain forests: They occur in areas where there is adequate rain fall. Coniferous trees like firs, redwoods and pines dominate these forests. There are also evergreen trees, with broad leaves.
• Temperate Deciduous forests: Here, moderate temperature occurs. The trees like poplar and oak grow in these forests.
• Evergreen coniferous forests (or) Boreal forests: They are found in the South of arctic tundra. There will be long winters. The temperature will be mild in summer. The trees are represented by fir, pines, spruce and cedar which have needle-shaped leaves. There is less species diversity due to acidic soil.

Components of forest ecosystem

• The following are the different components of forest ecosystem:
• Abiotic factors
  • Organic and inorganic substances in soil and air, temperature, light and rainfall are some of the abiotic components. The minerals in the soil vary depending upon the type of forest.
• Biotic factors
  • Producers
    • They include mainly trees, shrubs and herbaceous plants .
    • The trees include Tectona grandis (Teak), Butea monosperma Dipterocarpus Quercus, pine , cedrus etc.
  • Consumers
    • Primary consumers: They include herbivores like flies, ants, bugs, beetles and spiders and large herbivorous animals such as deer, elephants, squirrels, mongoose etc.
    • Secondary consumers: Snakes, lizards, foxes, birds and feeding herbivores.
    • Tertiary consumers: Lion, tiger, etc are the top carnivores.
  • Decomposers
    • They include fungi like Aspergillus, Polyporus, Trichodendron and bacteria like Bacillus, Clostridium etc.
    • The rate of decomposition varies from forest to forest.