| Seeing the Forests for More than the Trees
David Taylor Abstract
 Assessing the health effects of deforestation is difficult because of the rate at which the world's forests are disappearing. From 1990 to 1995 alone, the world lost a total area of forest cover nearly twice the size of Italy. Deforestation, which is caused by human population growth and encroachment, clearance for agricultural production, and the growing worldwide demand for wood products, has been linked with effects ranging from local changes in climatic and disease patterns to global climate change and biodiversity loss. Deforestation is responsible for about 25% of net annual releases of carbon dioxide into the atmosphere and also lessens the amount of forest available to absorb greenhouse gas emissions. Deforestation also causes a tremendous loss of biodiversity worldwide. It is estimated that over the next 50 years deforestation will rank as the single greatest cause of species loss. The combined impact of such effects can be disastrous. For instance, changes in the forest habitat of disease vectors combined with the raised temperatures that accompany deforestation can result in disease epidemics. Loss of forest cover can cause flooding and siltation, which further affect disease vectors' environments. And emotional stress and other social effects result when, for example, entire communities are forced to relocate because of deforestation projects. The method of deforestation used may lead to further problems--fires set to clear land, for example, can cause air pollutant indices to skyrocket. The difficulty in placing a monetary or social value on things such as biodiversity, potential medicines, and climate change effects has made it difficult for policy makers to tackle the problems accompanying deforestation. But this may be starting to change. Some U.S. cities have begun choosing watershed acquisition as a substitute for building water treatment facilities. Internationally, options such as financial incentives for preserving forest lands and the use of more efficient and environmentally sound logging methods are being explored. The current technology for repairing the damage of deforestation is rough at best. Reforestation presents the potential for spreading disease if nonnative plant species are used to repopulate a denuded area, and does not address the issue of loss of biodiversity. Bioremediation seems promising for some types of clean-up, but more research must be done in order to identify existing species and engineer new ones that will adequately absorb the target toxins. But progress is being made into broadening the palette of tools available for reforesting the planet. Environmentalists point to "primary environmental care," analogous to primary health care, as a way that individual communities may participate in preserving the environmental resources upon which they are most dependent. And new methods for mapping the environment, such as geographic information system technology, are giving resource managers and public health experts a basis for working together.
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