FORESTS SHRINKING
Chapter 3. Signs of Stress: The Biological Base
Lester R. Brown, Eco-Economy: Building an Economy for the Earth
(W.W. Norton & Co., NY: 2001).
At the beginning of the twentieth century,
the earth's forested area was estimated at 5 billion hectares. Since
then it has shrunk to 2.9 billion hectaresan
area roughly double the world's cropland area. The remaining forests
are rather evenly divided between tropical and subtropical forests
in developing countries and temperate/boreal forests in industrial
countries.23
Deforestation is caused by the growing demand for forest products
and the growing conversion of forested land to agricultural uses.
This forest loss is concentrated in developing countries. From 1990
to 1995, the loss in these nations averaged 13 million hectares
a year, an area roughly the size of Kansas. Overall, this means
that the developing world is losing 6.5 percent of its forests per
decade. The industrial world is actually gaining up to an estimated
3.6 million hectares of forestland each year, principally from abandoned
cropland that is returning to forests on its own, as in Russia,
and the spread of commercial forestry plantations.24
Unfortunately, even these official FAO data do not reflect the gravity
of the situation. For example, tropical forests that are clearcut
or burned off rarely recover. They simply become wasteland or at
best scrub forest, but they are still included in the official forestry
numbers if they are not included in another land use category such
as cropland or building construction. The World Resources Institute's
Forest Frontiers Initiative issued a report in 1997 on the status
of the world's forests. They note that "hidden behind such familiar
statistics is an equally sobering reality. Of the forests that do
remain standing, the vast majority are no more than small or highly
disturbed pieces of the fully functioning ecosystems they once were."
The report notes that only 40 percent of the world's remaining forest
cover can be classified as frontier forest, which they define as
"large, intact, natural forest systems relatively undisturbed and
big enough to maintain all of their biodiversity, including viable
populations of the wide-ranging species associated with each type."25
Use of each of the principal forest productsfirewood,
paper, and lumberis
expanding. Of the 3.28 billion cubic meters of wood harvested worldwide
in 1999, over half was used for fuel. In developing countries, the
share was far higher, nearly four fifths of the total. In industrial
countries, roughly 14 percent of the wood harvested was used for
fuel, much of it the waste wood used by pulp and paper mills to
generate electricity and to provide process heat. Using the bark
and small branches for fuel, some paper mills are energy self-sufficient.26
Deforestation to satisfy fuelwood demand is extensive in the Sahelian
zone of Africa and the Indian subcontinent. As urban firewood demand
surpasses the sustainable yield of nearby forests, the woods slowly
retreat from the city in an ever larger circle, a process clearly
visible from satellite photographs taken over time. As the circles
enlarge, the transport costs of firewood increase, triggering the
development of an industry in charcoal, a more concentrated form
of energy with lower transportation costs.27
Logging also takes a heavy toll, as is evident in countries in Africa,
the Caribbean, and the Pacific. In almost all cases, logging is
done by foreign corporations more interested in maximizing the harvest
of forest products on a one-time basis than in managing forests
to maximize sustainable yield in perpetuity. Once a country's forests
are totally clearcut, companies typically move on, leaving only
devastation behind.28
Another loss of forests comes from clearing land for agriculture
and plantations, usually by burning, a loss that is concentrated
in the Brazilian Amazon and more recently in Borneo and Sumatra
in Indonesia. After losing 97 percent of the Atlantic rainforest,
Brazil is now destroying its Amazon rainforest. This huge forest,
roughly the size of Europe, was largely intact until 1970. Since
then, 14 percent of Brazil's rainforest has been lost. In 1999 alone,
17,000 square kilometers were deforested.29
The progressive loss of forest cover has both economic and environmental
consequences. Economically, the countries that have lost their exportable
supplies of forest products, such as Nigeria and the Philippines,
are now net importers of forest products. Also lost are the jobs
and income that their forest industries once provided.30
The environmental effects of deforestation are becoming all too
visible. Scores of countries are suffering from disastrous flooding
as a result of deforestation. In 1998, the Yangtze River basin,
which has lost 85 percent of its original tree cover, experienced
some of the worst flooding in its history. In 2000, Mozambique was
partially inundated as the Limpopo overflooded its banks, taking
thousands of lives and destroying homes and crops on an unprecedented
scale. The Limpopo river basin, which has lost 99 percent of its
original tree cover, will likely face many more such floods.31
While deforestation accelerates the flow of water back to the ocean,
it also reduces the airborne movement of water to the interior.
The world's forests are in effect conduits or systems for transporting
water inland. Eneas Salati and Peter Vose, two Brazilian scientists
writing in Science, observed that as moisture-laden air from
the Atlantic moves westward across the Amazon toward the Andes,
it carries moisture inland. As the air cools and this moisture is
converted into rainfall, it waters the rainforest below. In a healthy
rainforest, roughly one fourth of the rainfall runs off into rivers
and back to the Atlantic Ocean. The other three fourths evaporates
and is carried further inland, where the process is again repeated.
It is this water cycling capacity of rainforests that brings water
inland to the Amazon's vast western reaches.32
If the rainforest is burned off and planted to grass for cattle
raising, then the cycling of rainfall is dramatically alteredthree
fourths of the rainfall runs off and returns to the sea the first
time it falls, leaving little to be carried inland. As more and
more of the Amazon is cleared for cattle ranching or farming or
is degraded by loggers, the capacity of the rainforest to carry
water inland diminishes. As a result, the western part of the forest
begins to dry out, changing it into a dryland forest or even a savanna.33
The burning and cutting of the Amazonian rainforest could also affect
agriculture in regions to the south. As the air masses moving inland
from the Atlantic reach the Andes, they turn southward, carrying
moisture with them. It is this moisture that provides part of the
rainfall in the agricultural regions of southwestern Brazil, Paraguay,
and northern Argentina. As the deforestation of the Amazon progresses,
the flow of moisture to these farming areas will likely diminish.
Efforts to boost farm output by clearing land in the eastern Amazon
basin could reduce farm output in southwestern Brazil.34
A similar situation may be developing in Africa, where deforestation
and land clearing are proceeding rapidly as the demand on firewood
mounts and as logging firms clear large tracts of virgin forests.
As the forest area shrinks, the amount of rainfall reaching the
interior of Africa is diminishing. A comparable trend is unfolding
in China. Wang Hongchang, a Fellow of the Chinese Academy of Social
Sciences, cites deforestation in the southern and eastern provinces
of China as a key reason for the rainfall decline in the country's
northwest, the area where the dust bowl is forming.35
A number of countries now have total or partial bans on logging
in primary forests, including Cambodia, China, India, New Zealand,
the Philippines, Sri Lanka, Thailand, and Viet Nam. Additionally,
about 3 million square kilometers, accounting for roughly 9 percent
of the earth's remaining forest area, are set aside as parks or
nature preserves or for other conservation reasons. In some cases,
the forests that are set aside are carefully protected, but all
too often these "paper parks" exist only in theory and in the meaningless
laws that set them up.36
ENDNOTES:
23. World forested area from Matthews et al., op. cit. note 4, pp.
3, 16; world cropland from FAO, op. cit. note 3.
24. FAO, Agriculture: Towards 2015/30, Technical Interim Report
(Geneva: Economic and Social Department, April 2000).
25. Forest Frontiers Initiative, The Last Frontier Forests: Ecosystems
and Economies on the Edge (Washington, DC: WRI, 1997).
26. FAO, op. cit. note 3.
27. Alain Marcoux, "Population and Deforestation," in Population
and the Environment (Rome: FAO, June 2000).
28. Nigel Sizer and Dominiek Plouvier, Increased Investment and
Trade by Transnational Logging Companies in Africa, the Caribbean,
and the Pacific (Belgium: World Wide Fund for Nature and WRI Forest
Frontiers Initiative, 2000), pp. 21-35.
29. Deforestation in Brazil from Geoff Dyer, "Brazilian Forest Logging
Escalates," Financial Times, 13 April 2000; Brazilian Embassy, Environment
Section, response to William F. Laurance et al., "The Future of
the Brazilian Amazon," Science, 19 January 2001, from discussion
with author, 22 January 2001, with data from the Brazilian National
Institute for Space Research (INPE), ; Indonesia
in Diarmid O'Sullivan, "Indonesia Faces Fires Disaster," Financial
Times, 9 March 2000; "Indonesia Warns Planters to End Fires or Face
Jail," Reuters, 15 March 2000.
30. Lester R. Brown, "Nature's Limits," in Lester R. Brown et al.,
State of the World 1995 (New York: W.W. Norton & Company: 1995),
p. 9.
31. Yangtze flooding from "Flood Impact on Economy Limited," China
Daily, 1 September 1998; Doug Rekenthaler, "China Survives Fourth
Yangtze Flood Crest as Fifth Begins its Journey," Disaster Relief,
11 August 1998; Mozambique flooding from "Aid Agencies Gear Up in
Mozambique Flood Rescue Effort," CNN, 1 March 2000; loss of forest
cover from Carmen Revenga et al., Watersheds of the World (Washington,
DC: WRI and Worldwatch Institute, 1998).
32. Eneas Salati and Peter B. Vose, "Amazon Basin: A System in Equilibrium,"
Science, 13 July 1984, pp. 129-38.
33. Ibid.
34. Ibid.
35. Deforestation in Africa from WRI, op. cit. note 5, pp. 90-95;
Wang Hongchang, "Deforestation and Desiccation in China: A Preliminary
Study," study for the Beijing Center for Environment and Development,
Chinese Academy of Social Sciences, 1999.
36. Bans on logging from "Over 11 Million Hectares of Forest Cover
are Lost Throughout the World Each Year," Environmental News Network,
March 1999; U.N. Environment Programme, Global Environment Outlook
2000 (London: Earthscan, 1999), pp. 78-80; protected forest area
estimate from FAO, op. cit. note 24.
Copyright
© 2001 Earth Policy Institute
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