Environmental Engineering Reference
In-Depth Information
what the alternatives may be. Passing legislation which cannot be enforced is
meaningless. We have also got to be economically realistic. Brazil has one of the largest
areas of this natural resource. For Brazil to cease development of that resource for the
global good is not feasible. It is often pointed out that many developed countries cleared
their own forests centuries ago. Why should developing countries not benefit from the
use of available forest resources? Most of them are heavily overburdened by debt to the
developed countries or the World Bank, so much of the revenue earned from forest
exploitation goes into interest payments.
One suggestion to conserve forests has been the designation of national parks or nature
reserves. By 1990 there were about 550 tropical forest parks which account for about 4
per cent of all tropical forests. There has also been a scheme to offset debts to developed
countries in exchange for retaining forest lands. In 1991 Mexico agreed a debt-for-nature
swap with Conservation International, which agreed to purchase and write off US$4
million worth of Mexican debt from foreign creditors. In return the Mexican government
agreed to invest US$2ยท6 million in rain forest conservation.
There is considerable scientific debate about the area of reserved land which is needed
to sustain suitable habitats for animals as well as plants. A few very large areas are seen
as more appropriate than many smaller sites. Unfortunately, even those sites which have
been agreed are not unaffected by exploitation. Many reserves exist on paper only, with
no policing or support, through lack of financial resources. It is not unknown for logging
to continue even in areas designated as parks. On the Indonesian island of Siberut, off
Sumatra, plans were advanced to log 1500 km
2
of virgin forest in a reserve and replace it
with an oil palm plantation.
Ideally what is needed for the rain forest is the maintenance of as much as possible of
the present variety of species and habitats and the restoration of damaged areas. At the
same time, the forests must be used to generate revenue at a greater rate than could be
obtained by clearance and replacement by some other use (Figure 28.10). The land must
be seen to be earning its keep, otherwise, in a world where economic pressures dominate,
the forests will disappear. Is this approach possible?
Estimates have been made of the economic returns of different types of land use in a
forested area of eastern Peru (Table 28.2). Low-intensity exploitation of nuts, fruit,
rubber and other products together with minor logging could generate greater income
than that from conventional methods of forest clearance and ranching. Even then, care
must be taken over transport and marketing. The products need to have some
international value to compensate for the loss of hard currency obtained from the sale of
tropical hardwood. Ironically the decrease in the sale of such timber could increase its
value unless demand declined, placing even greater pressure on the forests.
