Environmental Engineering Reference
In-Depth Information
countries to finance projects such as roads, mines, log-
ging operations, oil drilling, and dams in tropical
forests. Most countries also fail to value the ecological
services of their forests (Figure 8-7, left).
The depletion and degradation of a tropical forest
begin when a road is cut deep into the forest interior
for logging and settlement (Figure 8-10). Loggers then
use selective cutting to remove the best timber. Many
other trees are toppled in the process because of their
shallow roots and the network of vines connecting
trees in the forest's canopy. Although timber exports to
developed countries contribute significantly to tropi-
cal forest depletion and degradation, domestic use
accounts for more than 80% of the trees cut in develop-
ing countries.
After the best timber has been removed, timber
companies often sell the land to ranchers. Within a few
years, they typically overgraze it and sell it to settlers
who have migrated to the forest hoping to grow
enough food to survive. Then they move their land-
degrading ranching operations to another forest area.
According to a 2004 report by the Center for Interna-
tional Forestry Research, the rapid spread of cattle
ranching poses the biggest threat to the Amazon's
tropical forests.
The settlers cut most of the remaining trees, burn
the debris after it has dried, and plant crops in the
cleared patches. They can also endanger some wild
species by hunting them for meat. After a few years of
crop growing and rain erosion, the nutrient-poor trop-
ical soil is depleted of nutrients. Then the settlers move
on to newly cleared land.
In some areas—especially Africa and Latin Amer-
ica—large sections of tropical forest are cleared for
raising cash crops such as sugarcane, bananas, pineap-
ples, strawberries, soybeans, and coffee—mostly for
export to developed countries. Tropical forests are also
cleared for mining and oil drilling and to build dams
on rivers that flood large areas of the forest.
Healthy rain forests do not burn. But increased
burning (Figure 8-19), logging, settlements, grazing,
and farming along roads built in these forests results
in patchy fragments of forest (Figure 8-10, right).
When these areas dry out, they are readily ignited by
lightning and burned by farmers and ranchers. In ad-
dition to destroying and degrading biodiversity, their
combustion releases large amounts of carbon dioxide
into the atmosphere.
Solutions: Reducing Tropical Deforestation
and Degradation
There are a number of ways to slow and reduce
the deforestation and degradation of tropical
forests.
Analysts have suggested various ways to protect
tropical forests and use them more sustainably (Fig-
ure 8-21). One method is to help new settlers in tropical
Solutions
Sustaining Tropical Forests
Prevention
Restoration
Protect most diverse and
endangered areas
Reforestation
Educate settlers about sustainable
agriculture and forestry
Phase out subsidies that en-
courage unsustainable forest use
Add subsidies that encourage
sustainable forest use
Rehabilitation of degraded
areas
Protect forests with debt-for-nature
swaps and conservation easements
Certify sustainably grown timber
Reduce illegal cutting
Reduce poverty
Concentrate farming and
ranching on already-cleared
areas
Figure 8-21 Solutions: ways to pro-
tect tropical forests and use them more
sustainably. Critical thinking: which
three of these solutions do you believe
are the most important?
Slow population growth
Search WWH ::




Custom Search