Deforestation

Cultural practice involving removal of forest vegetation by cutting and burning to provide land for agriculture, grazing, settlement, industry, commerce, roads, etc., or by harvesting timber for building materials or fuel, usually in the form of charcoal. Loss of topsoil, braided streams choked with rocks and debris, habitat destruction, the systematic extermination of wildlife, and catastrophic floods are the inevitable results. In addition, in tropical areas where the above conditions are common, once the vegetative cover and its nutrient supply are removed, the freshly cleared oxisols harden to a rock-like state, making cultivation or re-establishment by natural vegetative all but impossible. Since the beginning of the 20th Century, that process has constituted one of the Earth’s most critical environmental problems. More than half of the rainforests in Africa, 45 percent of those in Asia, and 40 percent in Latin America have disappeared under the onslaught of spreading “civilization.” The rate of forest destruction is nothing short of breathtaking: globally about 55 acres are lost every minute, more than 80,000 acres disappear each day, and 30 million acres are wiped out each year. And those rates are not decreasing. Almost all of that deforestation occurs in the rainforests and open woodlands of the tropics (and certain sub-tropical regions). Not counting a few protected areas within reserves and parks, at the rates listed above all moist tropical forests could be long gone by 2050, except for isolated areas in Amazonia and the Zaire Basin. If no governmental conservation steps are imposed, countries such as Costa Rica, Haiti, Ivory Coast, Nigeria, and Sri Lanka are likely to be stripped of all their tropical forests between 2010 and 2015.

Deforestation is brought about by the following activities.

• Clearing of forests and woodlands to provide small-scale agricultural plots by local people, a process variously known as slash and burn, shifting cultivation, or swidden-fallow agriculture.
• Clearing of forests and woodlands to provide large-scale agricultural land for monoculture plantations, a variety of cash crops such as soybeans, or cattle ranching.
• Commercial logging of woods such as meranti, teak, mahogany, and ebony, etc., a process that removes trees, destroys or degrades habitat and ecosystems, and opens up previously forested land for large-scale agriculture or grazing.
• Felling of trees for firewood, charcoal, and building materials; the heavy lopping of foliage for fodder and heavy browsing of saplings by domestic animals like goats.

Tropical forest can contain up to 300 species of trees per hectare and many dozens of other species of herbs, shrubs, lianas, and epiphytes as well as thousands of insect species and many other animals. When the trees are cut all that diversity disappears and will not return. To compound the problem, the infertile soils of the humid tropics can not support agriculture for more than short periods. Consequently, local people engaged in slash and burn agriculture are forced to move on every several years and clear more forests in order to maintain the levels of production needed for survival. It should be noted that the swidden agriculture practiced by indigenous peoples of places like the Brazilian and Peruvian Amazonia is much less destructive than that of more contemporary farmers living at the edge of the forests. The indigenous peoples of the Amazon typically use a rotation system featuring a short cropping period, a long fallow period of ten years or more, and cut only the tallest trees while planting various crops in nearly concentric circles out from the plot’s center. That system may be ideally suited to the tropical environment. But the success of that type of swidden agriculture depends on low population density. When population rises so does food demand. Consequently, the fallow period must be shortened, resulting in eventual destruction of the forest habitat or loss of the soil itself through erosion or ferrallization (accumulation of indissoluble iron and aluminum oxides in the B-horizon). In this case, the environmental degradation blamed on swidden agriculture is thus not a direct result of an inappropriate system, but of overpopulation that leads to overexploitation of the land resources.

In addition, everyone should be aware of the disastrous failures large-scale conventional agriculture and monoculture plantations in Amazonia, such as Fordlándia, the 2.5 million acre rubber project of Henry Ford that never produced a rubber harvest and turned into an absolute fiasco, or Daniel Ludwig’s Jari forestry project, in which hundreds of millions of dollars were thrown away. Much of the soils of Amazonia, the Orinoco River valley, and the Zaire Basin are inherently inappropriate for large-scale agriculture and the monocultures that are typically planted after forest clearing are particularly prone to attack by erosion, insects, pests, plant diseases, or fire.

The inevitable consequences of deforestation include alteration of local, regional, and global climates through disruption of the carbon cycle (it is estimated that deforestation contributes one-third of all CO2 releases to the atmosphere caused by human actions); disruption of the hydrologic cycle through dramatic decreases in the evapotranspiration process, which causes hotter, drier climates; increased soil erosion through loss of protective vegetative cover; silting/choking of rivers, lakes, and impoundments as a result of soil and regolith erosion; flooding as a result of forest clearing, soil erosion, and dramatically increased surface run-off; extinction of native rainforest species through habitat destruction and alteration (between 50 and 100 tropical forest animal and plant species become extinct each day); and the loss of the world’s last surviving intimately resource-based indigenous (tribal) cultures.

Recent research has determined that significant alteration of existing tropical rain forests occurs at the edge in what are called forest fragments. Trees in these fragments, which are positioned in close proximity to cleared land, experience considerably higher stress than their interior counterparts and as a result die at rates up to three times faster. Those trees are replaced with fast-growth, short-lived species having low wood density and directly affects habitat and faunal diversity. In 2005, using 25 years of research conducted by the Biological Dynamics of Forest Fragments Project, now administered by the Smithsonian Tropical Research Institute, William F. Laurance and colleagues predicted that as much as 42 percent of forests in the Brazilian Amazon region would be severely degraded or destroyed by 2020. For an informative and directly pertinent read, see Michael A. Williams, Deforesting the Earth: From Prehistory to Global Crisis. Chicago: University of Chicago Press, 2003.

Real World Problem #1: Rainforests are places where certain trees have immense commercial value, either for rubber or as exotic hardwoods on the international lumber and veneer markets. Consequently, when either indigenous people or well-intentioned outsiders attempt to protect the rainforests and local residents from exploitation by the timber industry, grazing interests, or wealthy landowners, violence is a typical result. In the 1970s and 1980s, Chico Mendes (his full name was Francisco Alves Mendes Filho), a Brazilian rubber tapper, union leader, and environmental activist played an important part in the foundation of the National Council of Seringueiros (rubber tappers and extractive laborers). His passion was the creation of extraction preserves that would guarantee sustainable use and integrity of rainforests and also protect the poor seringueiros from ruthless exploitation by landowners. As a labor organizer he achieved international support for the struggle of the seringueiros against wealthy landowners and indirectly against the Brazilian federal government, which was reluctant to act owing to the political pressure brought by the landowners. In 1987 he received the “Global 500” award from the United Nations for his environmental activism. In December 1988, only a few days before Christmas, Chico Mendes was shot and killed in his home in Xapuri, Acre, Brazil, for opposing the destruction of the rainforest by a group of rich and powerful landowners, two of whom were prosecuted for his murder by the Brazilian government and convicted.

Real World Problem #2: In February 2005, Sister Dorothy Stang, a 74-year-old Catholic missionary, was shot to death by two hired gunmen in the Amazon state of Pará, Brazil. A naturalized Brazilian citizen, Strang had spent more than two decades defending the rainforests of Pará State and their desperately poor residents from rich and powerful loggers and ranchers. Lawlessness has long been common in the Amazon River region of central Brazil, where wealthy and politically powerful lumber companies and large-scale ranchers, backed by bands of armed thugs, ensnare poor workers in an endless cycle of debt and wage slavery that is widely practiced today in developing nations.

Real World Problem #3: In June 2014, a group of biologists and other eco-scientists published research (see reference below) that demonstrated that the effects of deforestation include how efficiently aquatic ecosystems function and deliver services that are vital to humans. Those effects in particular concern fish biomass production. Healthy forests produce far more fish while reduced forest cover results in reduced food web productivity. Although people who do not fish might think little of those findings, since many oceanic fish species use deltas, mangroves, brackish coastal lakes, and saltwater marshes as nurseries, those findings are of considerable significance.

Real World Example: Approximately 90 percent of the nation of Haiti was once covered by lush tropical forests. Today, less that two percent of those forests remain. As a result of the large-scale deforestation, torrential rains associated with tropical storms and hurricanes have washed the topsoil downslope into the ocean, leaving the land unsuitable for anything but marginally productive, small-scale agriculture. Much if not most of the western part of the Dominican Republic bordering Haiti and nearly the entire country of Haiti have been denuded of trees and woody plants by desperately poor Haitians, turning the landscape into a virtual desert devoid of topsoil, choking the rivers with soil, rocks, and debris washed from the increasingly bare slopes into the stream channels until the once tropical forest landscape resembles a desert. Worse yet, flooding caused by Hurricane Francis in the late summer of 2004 resulted in the deaths of well more than 2,000 Haitians, destruction of hundreds of settlements, and wide-spread violence as survivors fought each other and armed gangs for scarce food resources and uncontaminated drinking water. For a series of on-the-mark photos of deforestation, see http://www.solcomhouse.com/nasarainforest.htm.

Author’s Note: One recently documented instance of the destruction of an entire civilization because the people systematically deforested their environment was published in 2009 by researchers at the French Institute of Andean Studies in Lima, Peru, and the University of Cambridge in England. The researchers found that the Nazca people of western Peru — justly famous for their huge line drawings on an arid plateau that are only completely visible from the air — set the stage for their demise by deforesting the Ica Valley, about 120 miles south of Lima that was once a riverine oasis capable of supporting many people, allowing a huge El Niño-fueled flood to roar down the western slope of the Andes and devastate agriculture and settlement in the Valley about AD 500, a disaster from which the Nazca never recovered.

Reference
Tanentzap, Andrew J. Erik J. Szkokan-Emilson, Brian W. Kielstra, Michael T. Arts, Norman D. Yan, and John M. Gunn. 2014. Forests fuel fish growth in freshwater deltas. Nature Communications 5, 4077 doi:10.1038/ncomms5077; published 11 June 2014. Available at: http://www.nature.com/ncomms/2014/140611/ncomms5077/full/ncomms5077.html