1 Forests are the
prime example of natural areas that contribute heavily to human welfare by
acting as environmental buffers. Forests influence local and regional climates, generally by
making them milder. They help to provide a continuous flow of clean water; some forests,
notably tropical cloud forests, even increase the availability of water by intercepting moisture
from clouds. Watershed forests are particularly important because they protect soil cover on
site and protect areas downstream from floods and other harmful fluctuations in streamflow.
Removal or degradation of watershed forests and pastures can cause, great human suffering.
Without the sponge-like
effect of their vegetation, which retains moisture and releases it slowly,
the flow of water becomes erratic, leading to both floods and water shortages. The increased
rate of water run-off causes additional damage by stripping the soil away, depriving agriculture
of nutrients while clogging reservoirs, irrigation systems, canals and docks with silt, and
smothering coral reefs.
2 Watershed forests are being widely
devastated by clearance for agriculture, logging and
cutting for fuel, overgrazing, and badly managed road- building. The results can be extremely
expensive. It costs Argentina tens of millions of dollars a year to dredge silt from the estuary of
the River Plate and keep Buenos Aires open to shipping. Yet 80 per cent of the l00 million
tonnes of sediment that every year threaten to block the harbour comes from only 4 per cent of
the drainage basin, the small but heavily overgrazed catchment area of the Bermejo River 1800
kilometres (1100 miles) upstream.
3 Sedimentation as a result of unwise or careless use of watershed forests can drastically
reduce the economic life of reservoirs, hydroelectric facilities and irrigation systems. The
capacity of India's Nizamsagar Reservoir has been more than halved, from almost 900 million
cubic meters (1170 cubic yards) to less than 340 million cubic metres (440 cubic yards). Now
there is not enough water to irrigate the 110,000 hectares (270,000 acres) of sugar-cane and
rice for which it was intended, and hence not enough sugarcane to supply local sugar factories.
Deforestation
in northern Luzon in the Philippines has silted up the reservoir of the Ambuklao
Dam so fast that its useful life has been reduced from 60 to 32 years. Such problems are not
confined to developing countries: it has been estimated, for example, that more than 1000
million cubic metres ( 1300 million cubic yards) of sediment are deposited every year in the
major reservoirs of the USA. Although they have not been calculated (indeed, probably cannot
be), the global costs of sediment removal, river dredging, reconstruction of irrigation systems
and loss of investment in expensive structures like dams must be huge.
4 Deforestation in India and Nepal
was probably the major cause of the recent spate of
disastrous floods in India and Bangladesh. Flooding costs India alone hundreds of millions of
dollars a year. Typical of such disasters was the Alakamanda episode during the 1970
monsoon, when the Himalayan river of that name burst its banks. It was the start of a disastrous
flood, without precedent in the river's history. Whole villages were carried away and enormous
loads of silt were dumped downstream, ruining irrigation systems in the plains of Uttar Pradesh.
Banks were eroded and debris carried down the tributaries built up huge natural dams at the
confluence with the main river. As the water pressure increased the dams collapsed, leading to
flash floods. It was all the evidence local communities needed to demand an end to the
extensive deforestation of the local watersheds.
5 Elsewhere in Asia, deforestation and poor land management have caused fluctuations in
streamflows that have left high-yield varieties of rice with either too much or too little water,
thereby reducing rather than raising yields. Deforestation and other unwise environmental
manipulations (such as excessive channelization) probably also contributed to the severity of
floods that in recent years have struck countries as diverse as the USA and the Philippines.
Similarly, in Colombia, several major cities have to live with electricity rationing as a
consequence of widespread deforestation.
6 Besides protecting human communities from many forms of environmental harm, forests
provide a huge variety of goods and services: timber, sawnwood and panels for construction,
walls, doors, shuttering and furniture; pulp- wood for pulp, paper, cartons and rayon; poles,
posts, mining timbers and railway track sleepers; fuelwood, fodder, fruits, game meat, honey,
pharmaceuticals, fibres, resins, gums, dyes, skins, waxes and oils; and products used for beauty
care, amenity and recreation. Forests have unquestioned importance for industry and
commerce. The value of the annual world production of forest products exceeds $100,00
million and international trade is worth over $50,000 million. Thirty countries (eight of them
developing countries) each earn more than $100 million a year from exports of forest products,
and five of these each earn more than $100 million a year. Unfortunately, much of this
exploitation is not sustainable. Without conservation, the real income from forest products may
well decline.
7 Action on Forests
1 Forests particularly tropical forests, are succumbing to two sets of very different
pressures. One is the result of poverty combined with population growth—the desperate
struggle of peasant forest-dwellers to stay alive and earn a decent livelihood. The other is
the result of excessive or carelessly applied commercial demand, largely by people in
developed countries.
2 To save the forests from the first
set of pressures, we must greatly accelerate rural
development. Development must be based on conservation however, if it is not to destroy
forests just as thoroughly as does the current lack of development.
In the case of forest destruction by excessive firewood collection it would include
such
actions as the establishment of plantations for firewood large enough to meet higher levels
of demand than today's; the provision of alternative sources of firewood to take pressure
off the plantations and remaining vegetations; the restoration of the vegetation; and the
provision of stoves that use firewood more efficiently and alternative sources of energy such
as biogas (methane) and solar energy.
3 Dealing with the second set of
pressures requires insisting that all forest exploitation is
managed to high standards. The siting and management of timber operations should be such
that essential processes (especially watershed protection) are maintained. Unnecessary damage
to trees that are not used should be avoided. Felling programmes should be matched by
planting programmes, as far as possible using the species exploited, so that what is taken out is
replaced. Most timber companies are capable of taking all the necessary measures and should
undertake to do so, but governments should make sure that they are capable of inspecting and
controlling the conduct of commercial logging operations before they start. |
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