After Deforestation
What happens after a forest is cut is very important in the regeneration of that forest. Different cutting techniques and uses of the land have diverse effects on the ground and surviving organisms that make up a rain forest.

In a tropical rain forest, nearly all of the life-sustaining nutrients are found in the plants and trees, not in the ground as in a northern, or temperate forest. When the plants and trees are cut down to sow the land, farmers usually burn the tree trunks to release the nutrients necessary for a fertile soil. When the rains come, they wash away most of the nutrients, leaving the soil much less fertile. In as little as 3 years, the ground is no longer capable of supporting crops.

When the fertility of the ground decreases, farmers seek other areas to clear and plant, abandoning the nutrient-deficient soil. The area previously farmed is left to grow back to a rain forest. However, just as the crops did not grow well because of low nutrients, the forest will grow back just as slow because of poor nutrients. After the land is abandoned, the forest may take up to 50 years to grow back.

Another type of farming practiced in rain forests is called shade agriculture. In this type of farming, many of the original rain forest trees are left to provide shade for shade-loving crops like coffee or chocolate. When the farm is abandoned, the forest grows back very quickly, because much of it was left unharmed in the first place. After this type of farming, forests can grow back as quickly as 20 years.

Other types of farming can be more devastating for forest regrowth. Intensive agricultural systems use large quantities of chemicals like pesticides and fertilizers. These chemicals kill a lot of the living organisms in the area, seeping into the soil and washing into the surrounding areas. On banana plantations, pesticides are used on the plants and in the soil to kill pest animals. However, these pesticides also kill other animals as well, and weaken ecosystem health. Banana plantations also use irrigation ditches and underground pipes for water transport, changing the water balance of the land. After the abandonment of a banana plantation, or other intensive agricultural system, it can take many centuries for a forest to regrow.

Figures 3a and 3b. Deforestation in continental Southeast Asia (excludes Malaysia and Indonesia) from 1973 to 1985. The dark gray represents forest, the lighter areas deforestation. The white box-like areas on the 1985 map are places for which no satellite information was avaliable. During this time period, about 50,000 square miles was deforested. China and India are included on the map but no assessment of their forest cover was made. Click either image to enlarge.

A study in Indonesia found that when only 3% of the trees were cut, a logging operation damaged 49% of the trees in the forest. Yet, even with that much damage, the rain forest will grow back relatively quickly if left alone after selective logging, because there are still many trees to provide seeds and protect young trees from too much sun.

Clearcutting is much more damaging to a tropical rain forest. When the land is commercially clearcut and all of the trees removed, the bare ground is left behind with very little regrowth. Unlike when the farmer cleared the land, there are almost no nutrients left behind because all the tree trunks were removed. A clearcut forest can require many years to regenerate-in fact, scientists do not know how long it takes for a clearcut forest to grow back.

The Future
The deforestation of tropical rain forests is a threat to life worldwide. Deforestation may have profound effects on global climate and cause the extinction of thousands of species annually. Stopping deforestation in the tropics has become an international movement, seeking ways to stop the loss of rain forests.

Because the loss of rain forests is driven by a complex group of factors, the solutions are equally complex. Simple solutions that do not address the nature of world economics and rain forest ecology have little chance of succeeding. The future requires solutions based on solving the economic crises of countries holding rain forests, as well as improvement of the living conditions of the poor people often responsible for deforestation.

NASA Missions to Study Deforestation
NASA's Earth Science Enterprise future plans to study the effects of deforestation include continuing analyses using data from such instruments as the Enhanced Thematic Mapper Plus (ETM+), scheduled for flight on Landsat-7, and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Moderate Resolution Imaging Spectroradiometer (MODIS), scheduled for flight on the EOS AM-1 satellite. The observational capabilities and scientific studies planned as part of the Earth Science Enterprise, including the Earth Observing System, will help to assess the impacts of deforestation on the global climate system. An overarching objective of the Earth Science Enterprise is to improve our understanding of the causes and effects of climatic and environmental change so that we may become more effective and efficient managers of our natural resources, as well as mitigate potential impacts from natural disasters.

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Tropical Deforestation
Why Deforestation Happens
The Rate of Deforestation
Deforestation and Global Processes
After Deforestation