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A forest is an area with a high density of trees (or, historically, a wooded area set aside
for hunting). There are many definitions of a forest, based on various criteria [1]. These
plant communities cover large areas of the globe and function as animal habitats,
Forests can be found in all regions capable of sustaining tree growth, at altitudes up to the
tree-line, except where natural fire frequency is too high, or where the environment has
been impaired by natural processes or by human activities. As a general rule, forests
dominated by angiosperms (broadleaf forests) are more species-rich than those
dominated by gymnosperms (conifer, montane, or needleleaf forests), although
exceptions exist (for example, species-poor aspen and birch stands in northern latitudes).
Forests are differentiated from woodlands by the extent of canopy coverage: in a forest
the branches and foliage of separate trees often meet or interlock, although there can be
gaps of varying sizes within an area referred to as forest. A woodland has a more
continuously open canopy, with trees spaced further apart, which allows more sunlight to
penetrate to the ground between them (see also savanna).
A decidous broadleaf (Beech) forest in Slovenia.
View of a lake from within a forest.
A coniferous (pine) forest
A forest on San Juan Island in Washington.
Maple and Oak (broadleaf, deciduous) forest in Wisconsin in winter.
Rainforest
The largest tropical rainforests exist in the Amazon Basin,alaska,africa,eastern
australia,south eastern asia,central america ,etc
Rainforests are characterized by high rainfall, with definitions setting minimum normal
annual rainfall between 2000 mm and 1750mm
Rainforests are home to two-thirds of all the living animal and plant species on the planet.
It has been estimated that many hundreds of millions of new species of plants, insects and
microorganisms are still undiscovered. Tropical rain forests are called the "jewels of the
earth", and the "world's largest pharmacy" because of the large amount of natural
medicines discovered there. Rainforests are also often described as the "Earth's lungs", [1].
The undergrowth in a rainforest is restricted in many areas by the lack of sunlight at
ground level. This makes it possible for people and other animals to walk through the
forest.
Fauna
Rainforests support a very broad array of fauna including mammals, reptiles, birds and
invertebrates. Mammals may include primates, felids and other families. Reptiles include
snakes, turtles, chameleons and other families. Birds include such families as vangidae
and Cuculidae.
There are several common characteristics of rainforest trees. Rainforest species
frequently possess one or more of the following attributes not commonly seen in trees of
drier climates.
. Large leaves are common among trees and shrubs of the understorey and forest floor
layers. When they reach the canopy new leaves will be smaller. The large leaf surface
helps intercept light in the sun-dappled lower strata of the forest and are made possible
because the lower layers are largely protected from winds which damage large leaves in
the canopy. Canopy leaves are usually smaller than found in understory plants or are
divided to reduce wind damage. The leaves of rainforest understorey trees also often have
drip tips which facilitate drainage of precipitation off the leaf to promote transpiration
and inhibit the growth of microbes and bryphytes which would damage or smother the
leaf.
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Other characteristics that are more frequent in rainforest tree species than in drier forests
include:
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Exceptionally thin bark, often only 1-2 mm thick. It is usually very smooth,
although sometimes covered with spines or thorns.
Cauliflory, the development of flowers (and hence fruits) directly from the trunk,
rather than at the tips of branches.
Large fleshy fruits attract birds, mammals, and even fish as dispersal agents.
[edit] Rainforest layers
The rainforest is divided into four different parts, each with different plants and animals,
adapted for life in that particular area.
Emergent layer
This layer contains the emergents, a small number of very large trees which grow above
the general canopy, reaching heights of 45-55 m, a few species rarely to 60 m or 70 m
tall. They need to be able to withstand the hot temperatures and dry winds. Eagles,
butterflies, bats and certain monkeys inhabit this layer.
Canopy layer
The canopy layer contains the majority of the larger trees, typically 30-45 m tall. The
densest areas of biodiversity are found in the forest canopy, a more or less continuous
cover of foliage formed by adjacent treetops.
The canopy, by some estimates, is home to 40% of all plant species, suggesting that
perhaps half of all life on Earth could be found there. The fauna is similar to that found in
the emergent layer, but more diverse. A quarter of all insect species are believed to exist
in the rainforest canopy.
.
Understory layer
There is a space between the canopy and the forest floor, which is known as the
understorey (or understory). This is home to a number of birds, snakes, and lizards, as
well as predators such as jaguars, boa constrictors, ocelots, and leopards.
Armadillos also live here. The leaves are much larger at this level. Insect life is also
abundant. Many seedlings that will grow to the canopy level are present in the
understory. 5% of the sunlight shining on the rainforest reaches the understory.
Forest floor
This region receives only 2% of the rainforest's sunlight. Thus, only specially adapted
plants can grow in this region. Away from river banks, swamps and clearings where
dense undergrowth is found, the forest floor is relatively clear of vegetation, as little
sunlight penetrates to ground level. It also contains decaying plant and animal matter,
which disappears quickly due to the warm, humid conditions promoting rapid decay.
Wildlife
The term wildlife refers to living organisms that are not in any way artificial or
domesticated and which exist in natural habitats. Wildlife can refer to flora (plants) but
more commonly refers to fauna (animals).
Wildlife is a very general term for life in ecosystems. Deserts, rainforests, plains, and
other areas—including the most built-up urban sites—all have distinct forms of wildlife
Rainforest Wildlife
Rainforest, Thailand
Rainforests may contain one-half of all wildlife species on Earth
Tropical rainforests are known for their high biodiversity. This means that they have a higher
number of different species and varieties of plants and
Often called the king of the jungle, the jaguar is the third largest cat following lion and tigers.
Being less aggressive than the other two, the jaguar is a very territorial animal. Because of their
dappled coats, they blend in perfectly with the light on the forest floor where they thrive.
Unfortunately, many these jaguars are hunted because of their coats, which have a very high
price on the market
Northern Grown bandicoots (Isoodon macrourus) and Long-nosed bandicoots (Parameles
nasuta)
Both are omnivorous, eat insects and plants
Rodents
Southern Brush Rat (Rattus fuscipes) - insectivorous
Fawn-footed (Melomys ceruinipes) - mosaic-tailed rats with a mosaic-like pattern of scales on
their tails
House Mouse (Musmusculus) and the Black Rat (Rattus rattus) - omnivorous
Bats
Bats make up over half of the mammals of the rainforests with most of them being fruit eaters.
They feed primarily on liquid nectar from plants.
Vampire bats, however, is a distinct bat; it first flutters in front of the prey's face and then pierces
with their sharp teeth the skin of the prey: usually, a cow, pig, or goat. These bats' saliva contains
anticoagulants and anesthetics. Therefore the prey usually are not aware of cuts and the bat
freely feeds on flowing blood
The vegetarian bats are usually long tongued, and, being nocturnal, feed on flowers that only
open for them at night.
Could's Wattled Bat (Chalinolobus gouldii)
Occupies tree hollows and foliage and feeds on insects and invertebrates on the forest floor.
Little Bent-wing Bat (Miniopterus australis)
Lives in caves and mines. They hunt for flying insects below the canopy and along open canopy
spaces within heavily forested habitats.
Tapirs
Black and white Tapirs can be found in southeast Asia. The normally graze on riverbanks and
feed on grasses, buds, twigs, and fruits. They are good swimmers and they spend much time in
the water and aquatic plants are part of their diet.
Gorillas
Gorillas spend most of their lives on the forest floor. They climb into the
understory to feed and climb small trees to sleep in at night.
Monkeys
Within the branches of the canopy also live monkeys which swing playfully from branch
to branch. Most of them live in big groups of related families in the rainforests of Latin
America.
Spider Monkeys
The woolly and spider monkeys achieve additional stability by developing a prehensile tail, which
serves the function of a fifth limb
Black howler monkey in south america:
They engage in large hollering at dawn which is a form of territorial defense. The roar of the
males can be mistaken with the growling of jaguar.
West central africa mandrill monkey
The mandrill monkey has a brightly colored mask on its face which helps it to give strong visual
signals in the darkness of the forest.
Colobus monkey
Lives in the Guinean rainforest. It has a plump tail which helps in balancing during extended leaps
across the rainforest and serves the role of a rudder and a parachute. The Red Colobus Monkey
and black colobus monkey rarely venture on the forest floor.
Gibbons and Orangutans
They live in the rainforest of south east Asia
The Gibbons' arms are twice as long as those of a human and they almost reach the ground
when standing upright. They can leap to trees 20 feet apart.