Canopy
Suspended 40m above the ground is the canopy - a belt of tree crowns supported by enormous rainforest tree trunks. This is the most productive and diverse habitat on Earth - perhaps 40% of the world's species spend their lives among its branches. The canopy's function is to photosynthesise. Canopy trees arrange their leaves to soak up as much of the sunlight as possible and supply them with a continuous stream of water and nutrients from the soil far below, so that the process is uninterrupted from dawn to dusk.

Understorey
Beneath the canopy is a layer of trees adapted to living on the slim pickings of light that manage to penetrate the tree crowns above. These are mainly palms and slender, shade-tolerant trees, but amongst them are millions of canopy tree saplings. The saplings can survive for decades in the shade, waiting for a break in the canopy and a chance to join their relatives in the sunlight.

The understorey may appear to be puny in comparison to the canopy layer, but it still extends to 20m above the ground, as high as a typical oak forest.

Forest Floor
Down at the base of the enormous canopy trees is the forest floor. This is a dark, still and extremely humid world, alive in a way that's difficult to perceive. The inhabitants here have to eke out a living from the leftovers that fall from above - specks of light, dead leaves and over-ripe fruit. Most of them are involved in decomposing the leaf litter. Termites, soil mites, bacteria and fungi run an efficient recycling plant that returns the nutrients to the soil almost as fast as they arrive.

Lianas
The snaking, chaotic forms of lianas give jungles their iconic look. Lianas are woody climbing plants that climb the trees to get to the sunlight. Once up in the canopy they continue their growth from tree to tree, meshing the whole canopy together. Larger lianas can be centuries old and up to 1km long. They act like highways in the sky linking one tree crown with another and enabling animals up here to move around easily. Forests with more lianas typically have greater numbers of canopy species.

Drip-tips
Equatorial rainfall is so heavy that trees can easily get damaged during storms. Their solution is to shed the rain as quickly as possible. Each leaf has a spout called a drip tip which acts like a gargoyle on a church, channelling the water away in a quick but controlled manner so the tree crown isn't weighed down. Drip tips may protect the tree in another way. Releasing the rain at drop size reduces the risk of the thin soil below being washed away so easily. An unstable soil structure could spell disaster for the larger trees.

Shade-tolerant plants
Just 1% of the tropical sunlight makes it through the dense forest canopy. On the forest floor only tiny fragments of sunlight flit across the ground. Plants below the canopy have to survive on these sun flecks. To maximise exposure, they carefully lay out large leaves in rows or rosettes, so that no leaf overlaps another. Some coat the undersides of their leaves in a purple pigment that reflects the poor light back through the photosynthesising cells.

Busy lizzies, spider plants, cheese plants and prayer plants that we often grow in our homes live in this way.

Leaf litter
There is no autumn in the evergreen rainforest. Leaves fall constantly throughout the year as they become old and inefficient. Dead leaves pile up on the forest floor and the decomposers move in - termites, soil mites, bacteria and fungi. Spurred on by the heat and humidity of the forest floor, they manage to decompose half of this leaf litter every six weeks, breaking the leaves down into molecules small enough to enter the roots of trees. The trees transport the nutrients back up to the canopy to make fresh leaves and the cycle continues.

Buttress roots
Rainforest trees weigh hundreds of tonnes and are some of the tallest living structures on Earth. Yet they are rooted in soil that's only a few centimetres thick. Because the rain falls so heavily here, much of the soil is washed away on a daily basis and the result is a thin, impoverished soil base. To compensate for their poor foundations, canopy trees build enormous buttress roots. They come in various shapes and sizes, but they all serve the same purpose - to stabilise the tree.

Root mat
Just a few centimetres below the surface, the forest floor is a rock-hard iron pan with very few nutrients in it. For trees to get the nutrients they need, they are forced to send their roots along the surface of the forest floor. The roots of each tree then weave around the trunks of others stretching far off into the jungle to create a muddle of interlacing wood called a root mat.

Mycorrhizae
Jungle trees are demanding and unable to meet their need for a constant stream of nutrients on their own. To help, they enlist a group of fungi called mycorrhizae. These permeate the forest soil in a mesh of fine threads, absorbing nutrients at an incredible rate and channelling them directly back into the tree roots. In return for their dedicated service, the trees reward the mycorrhizae with sugars that they make in the canopy leaves far above.

Fig trees
While other canopy trees bear fruit for only a few weeks, figs act like soup kitchens providing a year-round supply. Worldwide there are over 800 varieties of jungle fig and they are all regarded as 'keystone species' - without them many other species would struggle to survive. Even the infamous strangler figs, which take over prime spots by smothering the trees that stand in their way, are regarded as beneficial to the canopy world because of their generous production of fruit.

Bats
Bats are extremely important animals in the rainforest. A single colony of insect-eating bats can consume quarter of a million kilos of insects in one night. Worldwide, hundreds of tree species are pollinated by nectar-eating bats. Bat flowers resemble either open cups of nectar or shaving brushes doused in pollen. They all open at night and scent their petals with a musty smell. Fruit bats are magnificent seed dispersers. They can visit six species of fruiting tree and travel over 30km in a single night.

Termites
Without termites the jungle would grind to a halt. They are vital ecosystem engineers, breaking up fallen leaves, branches and trees and conditioning the forest soil. There are up to 200 species of termite in a single hectare of jungle and on any one fallen trunk there can be a dozen different types working on their part of the demolition process. Some termites hire decomposing machines to help them in their task. Fungus-gardening termites feed chunks of wood to a vigorous decomposing fungus that they grow deep within their mounds.

Ants
Ants are everywhere in the jungle - up trees, on trees, in trees, and under the trees - and they lead a thousand different lifestyles. Leaf-cutter ants march foliage cuttings through the understorey to their nests, where they feed them to fungi that they grow in galleries. Megaponera ants patrol the floor in small teams, searching for termite mounds which they raid and pillage. Army ants and driver ants live in colonies of millions. Their strategy is to form an ant carpet and move through the forest in a swarm, grabbing anything that crosses their path.

Big cats
In most jungles, the top predator is a big cat. South America has jaguars, Africa has leopards and in south-east Asia there are tigers and the rarely-sighted clouded leopard. The big cats feed mainly on larger ground herbivores, but some follow their prey into the trees. Ambush is their chief hunting method, not pursuit, so they tend to work alone. The pickings are better than you might think. There are more leopards in the African jungle than on the savannah.

Primates
Primates include monkeys, apes, lemurs and some nocturnal animals like the busbabies. These mammals are supremely adaptated to tree-dwelling. Binocular vision helps them judge distance, gripping hands and feet can grab branches and an intelligent brain deals with the challenges of their high-rise habitat. For most, the staple diet is fruit but others feast on leaves, insects, seeds, flowers and even the resin that drips from damaged trunks. Fruiting trees are scattered in the jungle, so many of these animals are highly social, ganging together to secure a ready supply of food.

Canopy insects
Canopy insects account for almost 90% of jungle species. There are millions of kinds of canopy butterfly, moth, fly bee, wasp, cricket, mantid, beetle and ant. These are the forest's most important pollinators and most plants use them for dispersal, enticing them in with flowers and strong perfumes. Canopy insects are eaten by virtually everything and may go to extremes to avoid predation. Many blend into the background by resembling leaves or sticks. Others ingest the poisons of the plants they eat and advertise their toxicity with flashy warning colours.

Canopy birds
The jungle canopy is home to an amazing array of canopy birds. Most spend their entire lives among the branches. They feed on the bounty of insects, fruit, flowers, seeds and small animals in the canopy, each type specialising in a particular foodstuff in a particular part of their complicated aerial world. As well as feeding in the canopy, they find homes there - nesting among the epiphytes or in holes in the trees.