|
|
|
|
|
Imperilled Riches FUELWOOD/BUILDING MATERIAL FAO estimates that 40% of the world (2.3 billion people) rely on fuelwood or charcoal as their primary source of energy for cooking and heating. Fuelwood consumption has increased 250% since 1960 (the world's population only increased by 90% since 1960) and the number of people relying on fuelwood is expected to reach 3 billion by the year 2000. The collection of fuelwood and building material from the rainforest remains an important cause of deforestation by settlers. For example, Honduras relies on the burning of fuelwood for 65% of the county's energy, while in some African nations the percentage is even higher. Recently the refuge camps, full of some 750,000 refugees, in eastern Zaire relied heavily on the collection of fuelwood from Virunga National Park, the mountain gorilla reserve. In just a few months over 20,000 acres of park was cleared for fuelwood and building material. ROAD CONSTRUCTION The construction of roads to access logging, oil, and mining sites in the rainforest opens vast stretches of forest to exploitation by landless peasants who are responsible for the majority of rainforest destruction today. Numerous government and development agencies have funded roads and highways that cross forest areas. One of the most famous is the Trans-Amazonian highway in Brazil which opened up the Roraima state to widespread invasion and deforestation by miners and colonists. Today a great threat to a portion of mainland Asia's remaining tropical forests is a planned road system connecting Ho Chi Minh City in South Vietnam to Kuming in southwestern China. HABITAT FRAGMENTATION Habitat fragmentation is a serious threat to biodiversity and patches of forest worldwide (also see chapters 9 and 10). As great expanses of forest are increasingly chopped into smaller blocks, edges effects alter the the flora and fauna or forests. Fragmented patches of forest are subject to drying winds that increase the frequency of tree falls. Tree falls tear gaps in the canopy, destroying its function of moderating the humidity, temperature, and heat conditions of the forest floor. These changes affect the species that inhabit the forest patch, usually reducing diversity. Many rare species that dwell in the deep primary forest are unable to cope with the new conditions and are replaced by more common, weedier species. The drier forest conditions also mean that agricultural fires set in the surrounding scrubland and savanna are more likely to burn through the forest patch. During the Indonesian and Brazilian fires of 1997 and 1998, such forest patches went up in smoke at an alarming rate. Fragmented forests also suffer a loss of biomass - up to 36% - in the first few years after fragmentation. CLIMATE CHANGE Global climate change initiated by global warming is expected to have wide-ranging effects for tropical rainforests (also see chapter 9). Changes in weather patterns, rainfall distribution, and temperature will result in the conversion of rainforest into drier forest in some areas and the conversion of other forms of forests into rainforest. Should sea levels rise, large tracts of rainforest and enormous areas of mangrove forest will be destroyed. Additionally, though tropical forests and their species have lived through significant climate changes in the past (Pleistocene and Holocene epochs), they have less resilience to climate change in the future due to fragmentation and degradation from human activities. In response to global climate change, communities will need to migrate, an action that will be more difficult because of habitat alteration and fragmentation. |
|
A World Imperilled |
Natural Forces Subsistence Activities Oil Extraction Mining War Cattle Pasture Fuelwood, Roads, Climate Population & Poverty |
| what's new | tropical fish | help support the site | madagascar | search | about | contact |
Copyright Rhett Butler 1994-2005 |
