Rainforests

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Rainforests
A forest is an area with a high density of trees.

• rainforests are characterized by high rainfall,
  and by definition have a normal annual rainfall
  between 68 inches to 78 inches, or more.(1750 mm
  and 2000 mm)

Rainforests are home to two-thirds of all the
living flora and fauna species on the planet. It
has been estimated that many hundreds of millions
of new species of plants, insects and
microorganisms are still undiscovered.
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Typical Tropical Rainforest Climograph

• temperature

• precipitation

Can you tell which hemisphere this rainforest is
within?
Southern Hemisphere
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Tropical Rainforests are forests that form near
the equatorial regions on the Earthand fit the
general rainy nature of the definition.
Average Temperature 22 C (72 F)
Annual precipitation 50-260 in.
As you can see from the bar graph, rainforests
are the wettest biomes on Earth.
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The Wettest Place On Earth
Mt. Waialeale is thought to be the wettest spot
on earth, receiving well over 400 inches of rain
a year!
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Temperate Rainforests can be found in North
America including the northwestern coast of the
United States and the Pacific coast of Canada.
The temperate rain forest has seasonal variation,
with summer temperatures rising to about 80F and
winter temperatures dropping to near freezing.
In the northernmost regions, winter may be cold
enough for some ice and snow.
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Rainforest Facts

• The tropical rainforest is a region of
  year-round warmth.

• Almost all rainforests lie near the equator.

• Rainforests are now one of the most endangered
  biomes, and cover less than 6 of Earth's land
  surface. But they are home to over 50 of all
  known species of living organisms.

• Tropical rainforests produce much of the oxygen
  for Earths atmosphere.

• Tropical Rainforests have very nutrient-poor
  soil, and are second only to deserts for this.

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Rainforest Flora Plants

• Curare, from a tropical vine, is used as an
  anesthetic, and to relax muscles during surgery.

• Quinine, from the cinchona tree, is used to
  treat malaria.

• A person with lymphocytic leukemia has a 99
  chance that the disease will go into remission
  because of the rosy periwinkle.

• More than 1,400 varieties of tropical plants are
  thought to be potential cures for cancer.

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Layers in the rainforest
Emergent trees
are widely spaced, and 100 to 120 feet tall with
umbrella-shaped canopies that grow above the
forest. Because emergents are exposed to drying
winds, they tend to have very small leaves.
This is an adaptation similar to what you would
find in the desert, and it is helpful in
conserving water for the plant.
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Layers, continued...
of 80-foot trees allows light to be easily
available at the top of this layer, but greatly
reduced below it.
The upper canopy
The upper canopy is home to many arboreal animals
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Layers, continued...
At the 60-foot level, there is little air
movement. As a result the humidity is constantly
high in this area.
In the lower canopy
As you move down through the canopy, life becomes
even more abundant
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Besides these three canopy layers, a
shrub/sapling layer receives about 3 percent of
the light that filters in through the canopies.
These stunted trees are capable of a sudden
growth surge when a gap in the canopy opens above
them.

• The ground layer Sparse plant growth.

Less than one percent of the light that strikes
the top of the forest penetrates to the forest
floor. Most areas of the forest floor receive so
little light that few bushes or herbs can grow
there. As a result, a person can easily walk
through most parts of a tropical rain forest.
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If the leaf canopy is destroyed or thinned for
any reason, the ground beneath is soon colonized
by a dense tangled growth of vines, shrubs and
small trees called jungle.
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The air beneath the lower canopy is always
humid. The trees themselves give off water
through the stomata of their leaves. This
process, called transpiration, can account for as
much as half of the rain in the Amazon rain
forest!
El Yunque in Puerto Rico
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Rainforest Flora Adaptations
Emergent Trees tiny leaves that allow them to
combat the drying effects of the sun and wind
they are exposed to.
With between 100-200 inches of rain per year,
some plants have adaptations that help them shed
water off their leaves. Many plants have drip
tips and grooved leaves for this purpose.
Trees from the lower canopy, and rainforest floor
have enormous leaves.
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Flora Adaptations, continued...
Some plants grow in the upper canopy on larger
trees to get sunlight. These are the epiphytes
such as orchids and bromeliads.
Many trees have buttress and stilt roots for
extra support in the shallow, wet soil of the
rainforests.
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Rainforest Fauna Animals
The adaptation of prehensile tails (tails that
can grip an object, and as such be used as an
appendage) is only seen in New World monkeys.
Monkeys from the Old World do not have this
adaptation.
Old World Africa and Asia New World South
America
Other characteristics are bright colors and sharp
patterns, loud vocalizations, and diets heavy in
fruits.
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Insects make up the largest single group of
animals that live in tropical forests.
They include brightly colored butterflies,
mosquitoes, frogs camouflaged stick insects, and
huge colonies of ants.
As said earlier, scientists estimate that more
than half of the entire world's plant and animal
species may live in tropical rain forests!
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What continent is this monkey from?
How do you know?
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