The Tropical
Rainforests are probably 60 million years old and cover about
1,000 million hectares of in the world - more than a quarter of
the total World forest cover of 3,869 ha (figures from the Food
and Agriculture Organisation of the United States survey 2000).
That's in the region of 8.3% of the total land area of our
planet, but this figure belies the extraordinary role which they
play in the conservation of biodiversity and regulation of the
World biosphere. They are the home to more than 13 million distinct
species of plants and animals - that's more than half of the world's total
number of species. These tropical forests contain:
- 90% of the world's invertebrate species
- 70% of all vascular plant species
- 30% of all bird species
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The diversity is truly staggering. In one 52 hectare area of
Sarawak, Malaysia, 1200 species of tree have been identified.
Compare that with the 700 species found in the entire area of
the United States!
THE DESTRUCTION
Currently 14 to 16 million hectares are being destroyed every
year. That equates to about 30 hectares (75 acres) per minute!
It is estimated that this is costing the World a species
extinction rate of 100 to 140 species per day or 3-5% of the total
world biodiversity pool every ten years! (This is because many
of the species found in the rainforests are unique to a specific
area and are very interdependent on one another for survival.)
There is now only a third of the area that there was in 1800,
although the highest rate of destruction has occurred in the past 50 years.
WHY ARE THEY BEING DESTROYED?
The three main reasons for the rainforests being cleared:
- Planting subsistence crops (60%)
- Logging for paper, building timber and fuel (22%)
- Commercial farming & grazing land for cattle (11%)
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A UNIQUE ASPECT OF THE RAINFOREST
One of the peculiarities of the rainforests is the poor and
thin layer of soil. In theory, a normal ecosystem would struggle
to survive on such land. However, the rain forests have evolved
their own "nutrient recycling". Most of the
ecosystem's nutrients are present in the plants, rather than the
soil; over 80% in fact. Under the conditions of high
temperatures and humidity and with an unbelievable number of
living organisms at work, leaves falling to the floor of the rainforest decompose
within six weeks, making their nutrients available in record
time (as opposed to a year
in a temperate zone deciduous forest). WHAT DOES THIS MEAN
FOR THEIR FUTURE?
Well, there is a major repercussion to this unique nutrient
recycling. When trees and vegetation are cleared and taken away
the systems nutrients go with them, ending 60 million years of
development and leaving very little in the way of soil
nutrients. As a result, the farmer or rancher who clears the
forest very quickly exhausts the meagre nutrient resources
remaining in the soil. The people who farm these areas are very
poor and do not replace the nutrients and so have to move on to
clear further areas ... and so on and so on. And because the
soil is so thin and poor it is very quickly eroded by the rains
and lost.
For these reasons it is very likely that, once an area of
rainforest is cleared it can never be truly replaced.
That said, their are many scientific efforts going on around the World,
investigating sustainability of the forests and ways of
revitalising cleared areas. WHAT IS THE
IMPACT ON THE EARTH?
I've already mentioned the loss of rainforest species, which
means a depletion of the World gene-pool and the resultant loss
of biodiversity. This also means the loss of countless
undiscovered drugs and remedies, as explored in the next
section. Another very important point is that the
trees of the rainforest act as vast reservoirs of carbon. When
they are burned or cut down and left to rot they release huge
amounts of carbon dioxide into the atmosphere, contributing to
the greenhouse effect. In fact, this is the second highest
contributor to the greenhouse gasses at around 25%. WHAT IS THE IMPACT ON MANKIND?
The rainforests are incredible reservoirs of natural chemicals
which the plants and animals have been developing for millions
of years to aid them in their defenses against disease,
infection, predators, and pests. Mankind has just begun
to scratch the surface of how these compounds can benefit it.
Tropical forests have been the source of 60% of the anticancer
drugs discovered in the last 10 years.
Already 25% of the drugs in use in Western medicine are derived
from rainforest plants, and yet we have examined only 1% of the
forests' total potential. We have to ask ourselves: "With
every hectare of forest cleared today, what possible miracle
drugs are being lost forever?" Here is a table of just some
of the drugs currently used, which were derived from rainforest
vegetation:
DRUG |
USE |
Cortisone |
active ingredient in birth control pills |
Curare |
muscle relaxant for surgery |
Diosgenin |
sex hormones, birth control pills, steroids,
asthma
and arthritis treatment |
Neostigmine |
used
to treat glaucoma; also provides a blueprint for synthetic
insecticides |
Novacaine, cocaine |
local anesthetic; cocaine; also served as a blueprint for less
toxic and less addictive anesthetics |
Quassia |
insecticide |
Quinine |
anti-malarial, pneumonia treatment |
Resperine |
sedative, tranquilizer |
Rotenone* |
pesticide, flea dip,
eradicates Colorado potato beetle, used to poison fish |
Strophanthus |
heart disease |
Strychnine |
emetic, stimulant |
Turbocuarine |
Originally used by natives to poison arrow tips. Muscle
relaxant for surgery; to treat muscle disorders like
Parkinson’s disease and multiple sclerosis. Cannot be
synthesized in the lab. |
vincristine & vinblastine |
several forms of cancer including acute
leukemia, advanced breast cancer, Hogkin’s disease |
* also known by the catchy little
name
1,2,6,6a,12,12a-hexahydro-2-isopropenyl-8,9-dimethoxychromeno[3,4-b]furo[2,3-h]chromen-6-one In
Sarawak a single species of tree, Calophyllum lanigerum, is
being studied for extracts which scientists have high hopes for
treating HIV and AIDS as well as tuberculosis. While it will be
some time before the benefits are seen, if the extract
eventually becomes a drug it could earn $300 million a year. RAINFOREST
NEWS August 2002 - Brazilian President Fernando
Henrique Cardoso announced on the 22nd August that the country
is establishing the largest rainforest national park in the
world as the country's contribution to the World Summit on
Sustainable Development. Covering 3.8 million hectares (9.4
million acres) of the northern Amazon along Brazil's boundary
with French Guyana, the Tumucumaque Mountains National Park
shelters rare jaguars, harpy eagles and 12 percent of all
primates known to exist in the entire Brazilian Amazon. WWF is
allocating US$1 million to help the Brazilian government
implement the park as part of the Amazon Region Protected Areas
initiative (ARPA), an unprecedented collaborative effort to help
fulfill the Brazilian government's promise to protect the
Amazon. Tumucumaque means "the rock on top of the mountain
symbolizing a shaman's fight with the spirits." July 2002 - In an agreement, called a
"debt-for-nature swap", the USA has canceled $5.5
million of Peru's debt to them, saving the Peruvian government
about $14 million in future payments. Instead, Peru will pay $10
million in local currency into a trust fund in Peru that will be
used for critical conservation work in 10 rainforest areas,
covering more than 27.5 million acres. Peru has more than 20,000
species of vascular plants and nearly 1,800 species of birds,
many of them found nowhere else in the World. The World Wildlife
Fund, The Nature Conservancy and Conservation International
together contributed more than $1 million to the project.
June
2002 - Conservation International announced that Marc Van
Roosmalen, a Dutch scientist working at Brazil's National
Institute for Amazon Research in Manaus, 1,800 miles northwest
of Rio de Janeiro, has discovered TWO new species of monkey.
Conservation International's President Russell Mittermeier said
"This once again demonstrates how little we know about
biodiversity, these are the 37th and 38th new primate species
described since 1990."
June
2002 - A new species of conifer, Xanthocyparis vietnamensis
(the golden Vietnamese cypress) discovered in North Vietnam,
growing on steep limestone ridges in a mountainous area. What is
so special is that they aren't just a new species, but from a
hitherto unknown genus. Daniel Harder, director of the
University of California at Santa Cruz (UCSC) Arboretum and a
co-discoverer of the new species, said "For us to find a
previously undescribed large tree like this indicates that there
is probably a lot more to be discovered there. It's comparable
to the recent discoveries of previously unknown large mammals in
Southeast Asia, like the giant muntjac and the saola, a type of
ox." June 2002 - The golden-crowned manakin, a
bird of the Amazon rainforest which was presumed to be extinct
45 years ago, has been rediscovered in the Pará region of
Brazil where logging and cattle raising on cleared land
predominates. "Forest destruction will remain a major
threat to the long term survival of this beautiful bird and
other wildlife of the area," warned Fábio Olmos who,
together with José Fernando Pacheco, rediscovered the bird. April
2002 - Around 40 environmental campaigners from Greenpeace,
disguised as builders, stormed a government building at 22
Whitehall, London. They occupied the building, yards from
Downing Street, for three hours, claiming that the government
had spent £260,000 on illegal sapele, logged from rainforests
in Africa for the doors and windows. Greenpeace claimed that
Tony Blair, the British Prime Minister, had broken a promise he
made two years ago, when he pledged to source all Government
timber from 'legal and sustainable' sources. April 2002 - At the sixth
meeting of the Conference of the Parties to the Convention on
Biological Diversity Greenpeace International gave Brazil with
the Golden Chainsaw Award for being the biggest impediment to
the forest work programme.
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