"The rainforest canopy is like an eighth continent, an archipelago of floating islands that encircles the globe in a belt above the equator. It remains home to more than half of all the animals and plants living on Earth." - Heroes film
 
RAINFORESTS
The term "rainforest" was first coined in 1898 by a German botanist named A. W. F. Schimper, to describe forests that grow in constantly wet conditions. They can occur where the annual rainfall is more than about 2,000 millimeters (80 inches) and spread throughout the year. Rain forests are found in temperate as well as tropical regions, but the best-known ones occur in a belt around the equator.

Tropical rain forests have been evolving for almost 200 million years.  Over the eons, many forms of life evolved, giving rise to the incredibly high species diversity we see in many rain forests today. A hectare (2.5 acres) of Malaysian rain forest, for example, can contain as many as 180 different species of trees, whereas a temperate forest would be unlikely to have more than ten. The same richness and variety is seen among smaller plants and animals, especially insects.
 

THE RAINFOREST CANOPY
The immediate impression of a rain forest is one of overwhelming greenery in which there is little evidence of other life. Of all the regions of the world, the tropics receive the most sunlight, but only one to two percent of this reaches the forest floor. Plants tend to occupy all available light and space at different levels above the ground, each filtering out more light, which successively reduces the amount of light and the temperature, while increasing the humidity. Each level of the forest has its own microclimate.

The densest layer of vegetation in most primary forests is at about 20-30 meters (65-100 feet) above the floor, where the canopy trees, laden with epiphytes and climbers, branch into countless umbrellas of leaves. This zone is exposed to the full glare of the sun, bathed in high temperatures. This is the powerhouse of the forest, where most of the photosynthesis takes place. Much of the flowering and fruiting also takes place in this zone, and attracts many insects and larger animals that consume the produce.

Members of canopy communities are essential to maintain the diversity and resilience of the forests they inhabit. Canopy-dwelling plants (“epiphytes”) constitute up to half of the total plant diversity of some wet tropical forests and provide crucial resources for a host of arboreal birds and mammals. Canopy structural elements such as foliage and twigs account for a tremendous "sieving" effect of fog in some forests, causing wind-borne precipitation and its accompanying nutrients and pollutants to be deposited locally. Because canopy organisms dwell at the atmosphere-forest interface, they can serve as indicator organisms to monitor changes in global climate and atmospheric conditions.

The forest canopy is defined by canopy researcher G. G. Parker as "the aggregate of all crowns in a stand of vegetation, which is the combination of foliage, twigs, branches, epiphytes and the interstices (air) in a forest." The nature of canopy studies is multidisciplinary; it includes such diverse fields as environmental biology, plant biology, forest ecology, meteorology, computer science, atmospheric science, statistics, and zoology. Although most canopy research has been conducted by scientists who work singly or in small groups, interdisciplinary research groups are just now coalescing to approach canopy questions from different perspectives and spatial scales, using a wide array of access and analytical tools such as construction cranes, hot-air balloons, and remote sensing.

In the last decade, a remarkable burgeoning of scientific interest in the canopy has occurred. The number of scientific publications on canopy structure has grown at a disproportionately rapid pace relative to the general field of biology. New methods of low-impact access to tree crowns with ropes, cranes, and remote sensing technology have enabled scientists to directly study the canopy. Heightened public interest in biodiversity, global climate change, and tropical deforestation has generated books, symposia, popular articles, and films about the canopy. Recognition of this has filtered to popular and political spheres; for example, in 1997, the Governor of Washington State signed a Proclamation to establish Forest Canopy Week. Thus, canopy researchers are poised to incorporate an unprecedented amount of information and interest in this long-overlooked field and communicate results to interested audiences.
 
 “The canopy is the powerhouse of the forest.  It’s where sunlight changes into stored energy.  It’s where trees reproduce.  It’s where the flowers and fruits are.  It’s where pollination takes place, where fruit dispersal takes place.  It is where light is turned into life…it’s where everything is happening in the forest." - N. Nadkarni, Heroes film