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There are probably very few truly virgin forests left on Earth. Most have been burned, replanted or otherwise influenced by humans at various times. Ecologists are replacing their model of natural forests as ancient pristine entities with models that characterize them as dynamic, unstable and short-lived1. Nonetheless, the scale and pace of anthropogenic deforestation in the past 200 years dwarfs anything seen before. The most endangered ecosystem types include tropical dry forests and mountain forest ecosystems, such as cloud forests. Overall, human activity has removed roughly half of
the worlds natural forests, with the greatest losses in densely
populated countries. With the exception of Russia, less than 1 percent
of Europes old-growth forests remain, while some 95
percent of the continental United States forests have been logged
since European settlement began 2.
Most forest remains in the least densely populated forested regions
the major equatorial rainforests of Central Africa, the Amazon
basin and the Southeast Asian islands of Sumatra, Borneo and New Guinea,
as well as the boreal forests of Siberia and North America3.
Pressures on forests include high population growth
rates, making demands on land for farming in particular; industrial
enterprise based on natural resources, such as for timber and pulp production;
and demand for fuelwood and charcoal, which consumed 80 percent of the
timber cut in developing countries in 19954.
Piecemeal forest removal has also fragmented forest regions, which has
a disproportionate effect on species diversity by limiting the ecosystems
ability to recover from catastrophes such as fires and by reducing species
mobility5.
Most of the 10 percent recorded loss of the worlds natural forests between 1970 and 1995 occurred in the tropics, where population growth rates are fastest6. Between 1990 and 1995, the greatest amount of forests were lost in Latin America, followed by Africa and Asia. Annual deforestation rates were highest in fast-growing and already densely populated countries exceeding 3 percent in Bangladesh, Pakistan, the Philippines and Jamaica7. Poverty and wealth distribution are also important determinants of forest survival. Many poor countries and communities rely heavily for income and exports on exploiting forest products, alongside agriculture, while richer countries and communities may have other sources of income. The fastest destruction often occurs when large numbers of people are forced to migrate into the forests, usually because of urban unemployment, rural land shortages, fast-growing populations, the creation of refugees or a combination of these. Government policies can also be important. Most forests in tropical countries are state-owned, so migration of people into forests usually requires official sanction as well as government-built infrastructure, such as roads and organized farming programs. The deforestation of the Brazilian Amazon has spread from east to west as roads and development projects have penetrated the forest. Much of Indonesias forest has been converted into farms as a result of the national transmigration program, which has moved some 4 million people from densely populated areas to thinly populated forested provinces such as Kalimantan and Irian Jaya.
Failures of governance also contribute by encouraging resource plundering.
In 1999, in the aftermath of the fall of President Suharto, the majority
of Indonesian timber on the international market was illegally logged8.
Globalization of trade in forest products, especially timber, encourages
the removal of control over forests from native people, who have the most
incentive to maintain forests for future generations. Poor forest management
has left natural forests unable to regrow and often vulnerable to forest
fires, such as those that spread through Indonesia in the 1990s. Natural forests once characterized as jungle
that required clearing are now increasingly regarded
as important ecological and economic resources for both nations and
the planet. They stabilize the landscape by generating rainfall and
maintaining soil, groundwater and river flows. They are also a major
cultural resource as the homelands and direct sources of natural wealth
for indigenous peoples, such as the reindeer herders of Siberia and
the tribes of the Amazon, Borneo and New Guinea. The economic value
of a sustainable harvest of fruits, nuts, rubber, rattan, medicinal
plants and meat frequently exceeds the one-off value of clear-felling.
Most countries eventually adopt conservation measures
to protect surviving natural forests often following a natural
disaster attributed to deforestation. In 1998, after floods did extensive
damage on the River Yangtze, China banned further logging in some watersheds
and launched a replanting program. Chinese scientists also partly blame
deforestation for the falling water flows in the Yellow River. In the past two decades, the temperate northern latitudes have seen a
modest increase in Moreover, the felling of old-growth forests continues,
often with state subsidies for instance in the northwest of the
United States and the temperate rainforests of the Canadian west coast.
Western and Japanese timber companies have frequently exported
their destruction of natural forests to tropical regions: Southeast
Asian forests are a major source of hardwood timber for Japan. The 1990s saw the first worldwide efforts to halt
the decline of tropical forests. Studies for the International Tropical
Timber Organization (ITTO) at the start of the decade found that less
than 1 percent of logging was carried out sustainably (with recovery
to a similar ecological value)9.
Consumer boycotts of tropical timber grew in protest, and by the end
of the decade more than 15 million hectares of forestry projects had
received certificates of their sustainability from the Forest Stewardship
Council, a coalition including foresters, conservation and community
groups, timber traders and certification organizations. Certified timber
products can command a premium price. Economists and environmentalists have also sought
to give tangible economic worth to the undoubted ecological value of
natural forests as watershed protectors, storehouses of biological diversity,
and recreational and spiritual assets. The 1992 Convention on Biological
Diversity gave countries new rights to the ownership of the genetic
resources in their forests, which could find value in pharmaceuticals
or new crops, although this has yet to prove profitable. Ecotourism,
a fast-growing industry, is being actively encouraged. The potential commercial value of fast-growing trees
planted to soak up carbon dioxide (CO2)
from the atmosphere and act as carbon sinks has also been
recognized and backed by the 1997 Kyoto Protocol on Climate Change.
Carbon credits earned by planting these forests will be tradeable with
countries wanting to offset them against emissions, which are limited
under the Protocol. However, management of sink forests to maximize
their carbon absorption often reduces their ecological value.
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Copyright AAAS 2000. |