What makes rainforests

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Magazine How one image captures 21 hours of a volcanic eruption. Science Why it's so hard to treat pain in infants. Canopy leaves act as trillions of tiny solar panels converting the strong sunlight to energy, and water evaporating from the trees contributes to the humid climate around tropical rainforests.

This makes them particularly vulnerable to air pollution. A recent study found that increased levels of nitrogen and phosphorous in the atmosphere from human activity can lead to alterations in the chemical make-up of the canopy soils which could have big impacts on the diversity of canopy life— the same way polluted runoff can cause algal blooms in water.

The emergent layer is comprised of the oldest and tallest trees. These keystone hardwood species like Brazil Nut, Mahogany and Kapok provide critical habitat for large birds and primates. This layer is threatened particularly by selective logging practices. Large emergent trees are targeted for their value as timber. Some species of birds like Macaws nest in large cavities found exclusively in these old growth trees and therefore suffer these losses hardest.

Additionally, although only one tree is cut, woody vines called lianas that are strung between trees often pull down others as the cut tree falls, and the infrastructure required to move logging equipment into the thick forest tears down trees along the way.

Although each layer of the rainforest is distinct, they are inextricably connected—by animals dispersing seeds and plants cycling nutrients up to the canopy and back down again. Research has even shown that trees communicate with each other via mutualistic relationships with fungi.

Damage done to one segment of the forest ripples down and outward, often having broader impacts than are immediately visible. Understanding these connections, both within the forest and to the wider global climate, highlights the need to tread carefully when it comes to rainforests.

Small, waxy leaves help trees in the emergent layer retain water during long drought s or dry season s. Lightweight seeds are carried away from the parent plant by strong wind s. In the Amazon rainforest, the towering trees of the emergent layer include the Brazil nut tree and the kapok tree. The Brazil nut tree, a vulnerable species , can live up to 1, years in undisturbed rainforest habitats. Unlike many rainforest species, both the Brazil nut tree and the kapok tree are deciduous —they shed their leaves during the dry season.

The animals living in the emergent layer of the Amazon rainforest include birds, bats, gliders, and butterflies. Large raptors, such as white-tailed hawks and harpy eagles, are its top predator s. In rainforests on the island of New Guinea, pygmy gliders populate the emergent layer. Pygmy gliders are small rodent s that get their name from the way flaps of skin between their legs allow them to glide from branch to branch.

Bats are the most diverse mammal species in most tropical rainforests, and they regularly fly throughout the emergent, canopy, and understory layers. Beneath the emergent layer is the canopy , a deep layer of vegetation roughly 6 meters 20 feet thick. The canopy blocks winds, rainfall, and sunlight, creating a humid , still, and dark environment below. Trees have adapt ed to this damp environment by producing glossy leaves with pointed tips that repel water.

While trees in the emergent layer rely on wind to scatter their seeds, many canopy plants, lacking wind, encase their seeds in fruit. Sweet fruit entice s animals, which eat the fruit and deposit seeds on the forest floor as droppings. With so much food available, more animals live in the canopy than any other layer in the rainforest.

The dense vegetation dulls sound, so many—but not all—canopy dwellers are notable for their shrill or frequent vocalizing. In the Amazon rainforest, canopy fruit is snatched up in the large beaks of screech ing scarlet macaw s and keel-billed toucan s, and picked by barking spider and howler monkeys.

The silent two-toed sloth chews on the leaves, shoots, and fruit in the canopy. Thousands and thousands of insect species can also be found in the canopy, from bees to beetles, borers to butterflies. Located several meters below the canopy, the understory is an even darker, stiller, and more humid environment.

Plants here, such as palms and philodendron s, are much shorter and have larger leaves than plants that dominate the canopy. Understory plants often produce flowers that are large and easy to see, such as Heliconia , native to the Americas and the South Pacific. Others have a strong smell, such as orchids. The fruit and seeds of many understory shrub s in temperate rainforests are edible. The temperate rainforests of North America, for example, bloom with berries.

Animals call the understory home for a variety of reasons. Many take advantage of the dimly lit environment for camouflage. The spots on a jaguar found in the rainforests of Central and South America may be mistaken for leaves or flecks of sunlight, for instance.

The green mamba, one of the deadliest snakes in the world, blends in with foliage as it slither s up branches in the Congo rainforest. Many bats, birds, and insects prefer the open airspace the understory offers. Amphibians, such as dazzlingly colored tree frogs, thrive in the humidity because it keeps their skin moist. Gorillas, a critically endangered species of primate , are crucial for seed dispersal.

Gorillas are herbivore s that move throughout the dark, dense rainforest as well as more sun-dappled swamp s and jungle s. Their droppings disperse seeds in these sunny areas where new trees and shrubs can take root. In this way, gorillas are keystone species in many African rainforest ecosystems. The forest floor is the darkest of all rainforest layers, making it extremely difficult for plants to grow. Leaves that fall to the forest floor decay quickly.

Decomposer s, such as termites, slugs, scorpions, worms, and fungi, thrive on the forest floor. Organic matter falls from trees and plants, and these organisms break down the decaying material into nutrient s.

The shallow roots of rainforest trees absorb these nutrients, and dozens of predator s consume the decomposers! Animals such as wild pigs, armadillos, and anteaters forage in the decomposing brush for these tasty insects, roots and tuber s of the South American rainforest.

Even larger predators, including leopards, skulk in the darkness to surprise their prey. Smaller rodents, such as rats and lowland pacas a type of striped rodent indigenous to Central and South America , hide from predators beneath the shallow roots of trees that dominate the canopy and emergent layer.

Rivers that run through some tropical rainforests create unusual freshwater habitats on the forest floor. The Amazon River, for instance, is home to the boto, or pink river dolphin, one of the few freshwater dolphin species in the world. Tropical rainforest s are mainly located between the latitude s of Such humid air produces extreme and frequent rainfall, ranging between centimeters inches per year.

Tropical rainforests are the most biologically diverse terrestrial ecosystems in the world. It is home to around 40, plant species, nearly 1, bird species, 3, types of fish, species of mammals, and 2. Red-bellied piranhas and pink river dolphins swim its waters. Jewel-toned parrots squawk and fly through its trees. Poison dart frogs warn off predators with their bright colors. Millions of mushrooms and other fungi decompose dead and dying plant material, recycling nutrients to the soil and organisms in the understory.

The Amazon rainforest is truly an ecological kaleidoscope , full of colorful sights and sounds. Temperate rainforest s are located in the mid-latitudes, where temperatures are much more mild than the tropics. Temperate rainforests are found mostly in coast al, mountainous areas. These geographic conditions help create areas of high rainfall. They are also much less sunny and rainy, receiving anywhere between centimeters inches of rain per year.

Rainfall in these forests is produced by warm, moist air coming in from the coast and being trapped by nearby mountains. Temperate rainforests are not as biologically diverse as tropical rainforests. They are, however, home to an incredible amount of biological productivity, storing up to metric tons of leaves, wood, and other organic matter per hectare metric tons per acre.

Cooler temperatures and a more stable climate slow down decomposition, allowing more material to accumulate. The old-growth forest s of the Pacific Northwest, for example, produce three times the biomass living or once-living material of tropical rainforests.

This productivity allows many plant species to grow for incredibly long periods of time. Temperate rainforest trees such as the coast redwood in the U. The bottom layer or floor of the rainforest is covered with wet leaves and leaf litter. This material decomposes rapidly in the wet, warm conditions like a compost pile sending nutrients back into the soil. Few plants are found on the floor of the forest due to the lack of sunlight.

However, the hot, moist atmosphere and all the dead plant material create the perfect conditions in which bacteria and other microorganisms can thrive. Stories, experiments, projects, and data investigations. Download issues for free.