Forests- the name, most people generally term synonymous with wildness, disorganized environment. For some rare nature lovers, however, a dense forest is no different from a heritage site. So in this article, let us have a bit of insight into how this diversity of wildness and natural heritage coexist in harmony in this environment. Forests occupy roughly 10% of the net land area in India, contrary to the 40% of global land remaining under forest cover. This discrepancy in forest cover is however one of the principle reasons why global warming has extended its claws deep into the root of this country. Anyway, in this article our focus will be mainly on the survival and interdependence of life in the forest ecosystem.
First let’s focus on the non-living, that is, abiotic, component of forests. These are the inorganic as well as organic substances present in the soil and atmosphere in addition to the minerals. One of the most important abiotic components is the dead organic debris, which mixes with soil to form an extremely fertile organic soil mixture where plants germinate and grow up in a jiffy. Moreover there are different light conditions due to complex stratification in plant community. To be more specific about the different light conditions, we find there are certain sections of the forest where there is unperturbed supply of sunlight, and these are zones where large trees grow up. Once large trees grow, the high density of braches and leaves at the top prevents sunlight from coming to the ground and hence we find at the base of huge trees we find ground vegetation and shrubs in high concentration.
Moving to those components of forests which we mostly see we find the biotic components. The most important part of any ecosystem, producers, are mainly trees that show greater degree of stratification specially in tropical moist deciduous forest. The most important factor which causes the difference between vegetation in various forests is the climate in which the forest has developed. Besides huge tress, an important part of the flora is constituted of shrubs and ground vegetation. In temperate coniferous forests however the shrubs and ground vegetation are insignificant because the temperature and soil conditions there promote the formation of large trees. In temperate deciduous forests, the dominant tree species are Quercus, Acer, Betula, Thuja etc where as in temperate coniferous forests, the producer trees are species of Abies, Picea, Juniperus and Rhododendron.
In case of a forest however, the pyramid of number, energy and biomass are all standing upright. A forest is characterized by densely populated trees. Hence its normal that the number of plants here will be the maximum, more than the number of animals or consumers. So the Pyramid of number is upright with producer at its base. It appears interesting though that if we consider the ecosystem to be a tree ecosystem i.e. individual component of a forest, the pyramid of number is inverted as we can find so many worms, insects, birds thriving on a single tree. Hence a tree ecosystem is quiet unstable in nature as damage of a single tree can destroy the entire ecosystem.
As per standard conventions, the consumers can be divided into 3 categories. Firstly, primary consumers are the herbivores that include animal feeding on tree leaves like ants flies, bees, bugs and spiders. However primary consumers also include those animals who depend on small plants, fruits of plants for their survival. They include the elephants, deer, mole squirrel etc.
Secondary consumers are those animals which consume primary consumers to meet their energy requirement. Examples may be cited as the snake, which derives its nutrition by consuming frogs, lizards, which consume insects to meet their requirement of food.
Tertiary consumers are top carnivores of a forest ecosystem like tiger and lion that consume secondary consumers as their food.
Now if we plot the energy pyramid of the forest ecosystem, we find that the tertiary consumers receive minimum amount of energy and form the apex of the pyramid where as the primary consumers receive the maximum amount of energy among the consumers and hence we find that the energy pyramid is upright as always for the different subdivision of consumers. In case of pyramid of biomass as well as pyramid of number, we find that in a forest ecosystem both the pyramids are upright. That is because, the net quantity of food produced is always maximum. The best part of a forest ecosystem is however that even if we include the different sublevels of consumers in the ecological pyramid, we find the pyramid is absolutely straight thus proving the stability of the plant ecosystem.
Decomposers are a wide variety of microorganisms that perhaps play the most important role in maintaining ecological balance and continuing the ecological cycle. Plants absorb nutrients and raw materials from the environment to start the cycle. If a cycle has to occur, these nutrients and raw materials must be returned to the environment. This restoration of natural resources is done to the environment by microorganisms like Fungi, Aspergillus, Coprinus, Polyporus, Ganoderma, Fusarium etc These micro organisms bring about the decomposition of complex dead organic matter of both plants and animals to simple forms, as was taken from the environment from the plants and hence helps in recurrence of the cycle. Due to high temperature in tropical rain forest, we find that the rate of decomposition by micro organisms is much higher there than in temperate forests.
In a forest ecosystem, the stability of the ecological cycle lies in the fact that a number of organisms occupy each of the trophic levels and hence this gives rise to a food web rather than a food chain. The stability of the food chain ensures that even if a particular type of species in the forest become rare due to natural conditions, the ecosystem does not loose its stability as it has got a large number of other animals occupying the same trophic level. Again, as stated earlier, the pyramids of biomass, number and energy are all upright.