Tropical Rainforests and the Great Nicobar Project
Context:
The ecological vulnerability of tropical rainforests has recently made headlines following opposition to the ₹92,000-crore mega infrastructure project on Great Nicobar Island.
Critics and political leaders have warned that building an international transhipment port, an airport, and a township will destroy approximately 160 sq. km of pristine rainforest, threatening India's ecology and the rights of local Nicobarese tribal communities.
Characteristics of Tropical Rainforests:
Geography and Climate:
Found primarily in the tropical zone around the equator, between the Tropic of Cancer and the Tropic of Capricorn.
They feature an equatorial climate that is consistently hot and humid year-round, receiving abundant rainfall of at least 2,000 millimetres annually.
Biodiversity Hotspots:
Despite covering a mere 6% of the planet's land surface, tropical rainforests are home to a staggering 80% of the world's documented species.
The Amazon rainforest is the largest globally, while Australia's Daintree rainforest is the oldest at approximately 180 million years old.
Structural Layers:
Emergent Layer:
The highest tier, featuring massive, umbrella-shaped trees exposed to full sunlight, strong winds, and heavy rainfall.
Canopy Layer:
Acts as a dense green roof, blocking around 95% of sunlight from reaching below.
It is rich in epiphytes (such as orchids, mosses, and lichens)—plants that live on tree surfaces and extract moisture directly from the air, acting as vital water-absorbing sponges for the ecosystem.
Understory Layer:
A dark, humid zone where native plants typically feature large leaves to capture minimal sunlight and brightly coloured flowers to attract pollinators.
Forest Floor:
Receives less than 2% of sunlight.
It relies heavily on a rich diversity of microorganisms to rapidly decompose and recycle the constant fall of dense organic matter.
Significance:
They are crucial carbon sinks that absorb carbon dioxide to tackle climate change, and they play an indispensable role in the global water cycle.
Around a quarter of modern medicines are derived from these forests.
Examples include quinine (from Cinchona trees) for malaria and compounds from the Madagascar rose periwinkle used to treat leukaemia.