User:AzzamJahangiri/Canopy (biology)

In biology, the canopy is the aboveground portion of a plant cropping or crop, formed by the collection of individual plant crowns.

In forest ecology, canopy also refers to the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms (epiphytes, lianas, arboreal animals, etc.). Forest canopies are important components of forest ecosystem ecology. They contribute significantly to certain ecological services such as biodiversity, carbon storage, water cycles, and climate regulation. These services contribute to the overall balance of the forest ecosystem. For example, The diverse communities that inhabit the canopy layer are thought to be involved in maintaining forest diversity, resilience, and functioning. Furthermore, forest canopies also regulate global climate by acting like "carbon sinks".

Sometimes the term canopy is used to refer to the extent of the outer layer of leaves of an individual tree or group of trees.[citation needed] Shade trees normally have a dense canopy that blocks light from lower-growing plants.

Forest canopy ecology
Forest canopies have unique structural and ecological complexities and are important components of the overall forest ecosystem. They are involved in critical functions such as rainfall interception, light absorption, nutrient & energy cycling, gas exchange, as well as providing habitats for a diverse range of wildlife. The canopy also has a role in modifying the internal environment of the forest by acting as a buffer for incoming light, wind, and temperature fluctuations.

Species diversity
The forest canopy layer supports a diverse range of flora and fauna. An estimated 50% of terrestrial biodiversity resides in forest canopies. 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. Due to this, forest canopies are arguably considered some of the most species-rich environments on the planet. It is now believed that the communities found within the canopy layer play an important role in the functioning of the forest, as well as maintaining diversity and ecological resilience.

Forest climate
Forest canopies contribute to forest microclimate by controlling and buffering variations in climatic conditions. Forest canopies intercept rain and snowfall, thereby buffering the effects of precipitation on the local climate. Forest canopies also buffer the effects of temperature within forests by creating vertical light gradients. Variations in forest microclimate are also driven by the structure and physiology of canopy trees and epiphytes. This produces feedback loops where forest microclimate both determines and is determined by the species identity, growth traits and forest stand composition of canopy trees.

Global climate
Forest canopies are significantly involved in maintaining the stability of the global climate. They are responsible for at least half of the global Carbon dioxide exchange between terrestrial ecosystems and the atmosphere. Forest canopies act as carbon sinks which reduce the increase of atmospheric CO2 caused by human activity. The destruction of forest canopies would lead to the release of carbon dioxide which would result in an increased concentration of atmospheric CO2. This would then contribute to the greenhouse effect, thereby causing the planet to become warmer.