|
There are two types of rainforests: tropical and temperate. The
two types share certain characteristics. For example, their
vegetation is dense, tall, and very green, and they are rich with
plant and animal species.
Tropical rainforests are located near the equator. More than half
of all tropical rainforests are found in South America. One-third of
the tropical rainforests are located in Brazil. Significant portions
of tropical rainforests are also located in Southeast Asia, the
Pacific Islands, and West Africa. Tropical rainforests only cover
about 7 percent of the earth's surface, but nearly half of the
world's species of plants and animals live in them.
The temperate rainforests are located in coastal regions. The
largest temperate rainforests are located in North America along the
north Pacific coast starting in Oregon and running over 1,200 miles
all the way to Alaska. Although this strip of forest may seem vast,
it is really only about 3 percent of North America's original
temperate rainforest. Some smaller temperate rainforests are located
along the southeast coast of Chile in South America, and small
coastal regions in the United Kingdom, Norway, Japan, New Zealand,
and southern Australia.
Rainforests are quickly disappearing. Some scientists estimate
that we are losing an area of rainforest the size of Pennsylvania
every single year. If this rate of deforestation continues, we may
lose all the rainforests within the next one hundred years.
Deforestation occurs for many reasons. In the United States,
widespread deforestation occurred along the Pacific coast more than
a century ago when people created settlements and cleared land for
farming. Currently, in many tropical regions, people are moving away
from overcrowded cities into forest areas. Once there, they clear
forest land to use as small farms. Commercial agricultural projects
also clear large plots of rainforest land. Logging and using
rainforest as pastureland also contributes to the shrinking of the
rainforest. Mining operations have led to massive erosion, which has
also wiped out large areas of rainforest.
In the United States, the National Park Service monitors and cares
for the rainforests. The following information was created by the
park services to help us better understand this important
resource.
"The temperate rainforests in the valleys of the [Pacific
Northwest] contain some of the most spectacular examples of
undisturbed Sitka spruce/western hemlock forests in the lower
forty-eight states. This ecosystem stretches along the Pacific coast
from Oregon to Alaska. Other temperate rainforests are found in
several isolated areas throughout the world. What defines a
rainforest quite simply is rain, and lots of it. Precipitation in
the rainforest along the Pacific coast ranges from 140 to 167
inches—12 to 14 feet—every year. The mountains to the east also
protect the coastal areas from severe weather extremes. Seldom does
the temperature drop below freezing in the rainforest, and
summertime highs rarely exceed 80°F."1
"All life, including you, is dependent on other life. In the
Olympic National Park's rainforests, interdependency is essential
for life to continue. When wind blows giant Sitka spruce trees over
and they fall to the forest floor, they become spongy nurse logs.
Seedlings find root in these dead trees and feed on the stored water
and nutrients found within them. As a seedling matures, it
establishes crucial connections with fungi beneath the forest floor.
Of course, fungi have needs too. In addition to all the sugars they
extract from the roots of their tree partners, they need fundamental
chemical building blocks, which they receive from microorganisms and
bacteria living in the forest floor. Lastly, and possibly most
importantly, are the dependencies of the "little ones." Bacteria and
blue-green algae seek the chemistry of clean wind, water, and soil
for the oxygen, nitrogen, carbon dioxide, and primary chemistry they
use to feed the forest. And the feedback loops go on and on and
on..."2
|
