Rainforests are the dynamic engine of the Earth’s biosphere; they fix carbon from the atmosphere, and the aspiration of plants in the rain forests produce nearly 10% of the oxygen we need to live (over 70% of the oxygen is generated by algae and plankton on the world’s oceans). They act as filters, pulling pollutants out of the air and fixing minerals into the soil, and help stem the tide of soil erosion; they are dynamic, and vividly alive, and critical to the life expectancy of our planet.
The biological diversity of tropical rain forests is staggering. Of the roughly 1.9 million named land species native to planet earth, over two thirds of them are found in tropical rain forests, ranging from Asia to South America to Africa, and places in between. 95% of the beneficial plants and plant compounds used for medicine, cosmetics and more are found in tropical rain forests, and this diversity is one of the great treasures of the world.
And it’s being lost, and lost rapidly, due to development and encroachment by urban areas. 30 years ago, rain forests covered 14% of the land area of the earth. It’s now under 6% and shrinking rapidly. At the current rate of deforestation, the last rain forest could be cut down by the 2040s.
There are several layers of impact to the loss of rainforest terrain and biomes. The first is simply conservation - when the last member of an animal species dies, that species has gone extinct. There is a strong emotional appeal to preserving wildlife, preserving wild lands, is very important to people. The second is climactic. Developing rain forest into cattle lands or crop lands leads to desertification, because of the shift in rainfall patterns and the fact that rainforest ecosystems keep most of the nutrients in plants, rather than the soil. The last impact is economic and medical; the rainforests are reservoirs of ecological diversity, and potentially domesticable plants and animals. Major research goes into finding plants and plant compounds that are tied to medical advances and present in plants and animals in the rainforest.
Rainforest deforestation impacts the planet, local and global economies. We’re going to focus on the local changes, and work from there, up the chain of events and causality. The typical cycle is that rain forest lands get clear cut and used for crop lands, then cattle grazing lands when the crops fail, then abandoned (or used for housing if conveniently located), when even grazing lands fail. This is part of a vicious cycle - most of the nutrients in a rain forest biome are tied in the living organisms, not the soil itself. When they’re clear cut, and burned, most of the resulting land is poor for agricultural use, low in phosphorus and nitrates, with soil that will blow away when the first wind storm hits. Soil exhaustion and salinization from over irrigation makes things even worse. This is, in many ways, analogous to strip-mining the soil, much as one would strip mine for copper or iron ore.
In an active and thriving rain forest, minerals and nutrients cycle quickly. When the rain forest is chopped down, those nutrients aren’t there any more. They’re shipped off as building materials or simply burned to clear the land. When grasses are seeded for cattle ranching, the soil is already starting depleted, and gets more so quickly. Eventually, the grass gets overgrazed, winds and rains come down and wash the soil into estuaries, and the process cycles even faster.
Erosion from deforestation is an attendant problem. The cover provided by the rain forest canopy keeps the tropical sunlight from baking the moisture out of the soils, and the aspiration of the plants helps capture rain clouds and seed clouds for rain. After the forest has been cleared, rainfall drops considerably. The tropical rain forest is a perfect example of a system where the combination of elements creates a whole greater than the sum of the parts.
There are several programs in place to try to preserve rain forests; the problems come from the fact that, in terms of local economics, it’s hard to convince a farmer that clearing more land to raise more crops and make more money is a losing proposition compared to leaving the rain forest in place as a refuge for vermin and predators. Trying to preserve islands of rainforest land hasn’t worked; the minimum area for viable rainforest biomes is around one hundred square miles, and most of the island experiments have been a tenth of that or less. Now, larger non governmental organizations are trying to buy up large tracts of rainforest land to keep as nature preserves, or to use as a basis for ecological tourism as a revenue stream to offset land use taxes, and the economic incentives for clear cutting.
Some efforts are being put in place to teach local farmers to work with the rain forest ecosystem rather than competing with it, using clearings in the rain forest for garden plots, and attempting to harvest the bounty of the rainforest directly. These have met a great deal of resistance because of the difficulties in balancing immediate short term profit with long term sustainability.
By: Adrian AdamsAbout the Author:
Posted by http://www.traveltheworld360.com
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Sep.1,2010
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