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Read this article to learn about the plant and animal biomass in forest ecosystem.
Plant Biomass:
Because of their size and longevity, trees have formed the most massive and complex ecosystems of the earth. The total amount of plant biomass per hectare is high. More than three-quarters of the total plant bio-mass in a mature forest is contained in trees, and that in the trunks generally exceeds that in the canopy and roots combined.
However, the contribution of the component parts of the trees to the total biomass is variable. It depends on the age of the individuals, as well as the stage of development of the forest ecosystem. Herbivores consume a relatively small, but variable proportion of the annual photosynthetic production.
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Up to 75% of this may enter the detrital or decomposer food chain, taking the form of litter. This supports a diverse population of soil organisms. The volume of this dead organic material (DOM) can be double that of the fresh leaf tissue.
The type of stratification and degree of structural development of the component plant life forms of the forest ecosystem depends on the amount of tree biomass and, especially, on the density and depth of tree canopy that has been shaped by the particular environmental conditions. Let us take the example of a tropical rain forest. The multi-layered tree canopies reduce the penetration of sunlight. Consequently, the growth of small non-arboreal forms beneath it is limited.
Animal Biomass:
In a forest ecosystem, the most dense animal population are found in the canopy and the soil. The tree-trunks and the canopy provide shelter for roosting, nesting and feeding to a variety of birds, including plant feeders, insect eaters and predators.
Arboreal animals — such as reptiles, and especially monkeys, squirrels, pine martens and sloths — show morphological adaptations, such as prehensile toes and nails.
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There are a small number of vertebrates living on the surface. They look for the openness of the forest and feeding opportunities. In temperate forest eco-systems, the ground-dwellers include the polecat, fox, wild cat, wild boar, the red and fallow deer, as well as larger ground-nesting birds, such as blackcock, grouse, capercailzie and turkey (in America).
The upper soil horizons are dominated by burrowing vertebrate and invertebrate animals as also microscopic decomposers.
The most numerous above-ground animals are the herbivorous, predatory and laprophytic insects. However, their populations fluctuate from year to year and often attain the level of pests causing damage.
The animal bio-mass of forests is small, but extremely varied, and along with it the complex structure and diverse food supply of the plant biomass provides a diversity of microhabitats for the animal population.
