[1][2][3] In forest ecology, the canopy is the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms (epiphytes, lianas, arboreal animals, etc.).
With an abundance of water and a near ideal temperature in rainforests, light and nutrients are two factors that limit tree growth from the understory to the canopy.
They are involved in critical functions such as rainfall interception, light absorption, nutrient and energy cycling, gas exchange, and providing habitat for diverse wildlife.
[11] The canopy also plays a role in modifying the internal environment of the forest by acting as a buffer for incoming light, wind, and temperature fluctuations.
It has been dubbed "the last biotic frontier" as it provides a habitat that has allowed for the evolution of countless species of plants, microorganisms, invertebrates (e.g., insects), and vertebrates (e.g., birds and mammals) that are unique to the upper layer of forests.
[13] It is believed that the communities found within the canopy layer play an essential role in the functioning of the forest, as well as maintaining diversity and ecological resilience.
Forest canopies act as carbon sinks, reducing the increase of atmospheric CO2 caused by human activity.
A method employed to avoid this problem is covering forest floor with plastic sheets and collecting the throughfall.