Washington, DC, December 7, 2006--A study published in the US journal Proceedings of the National Academy of Sciences has provided an optimistic outlook on global forest levels.
"Returning Forests Analyzed with the Forest Identity" provides evidence that forest cover in Europe, North America and Asia is expanding. The study also shows a positive correlation between economic development and forest conservation.
A new formula to measure forest cover, developed by researchers at The Rockefeller University and the University of Helsinki, in collaboration with scientists in China, Scotland and the USA, suggests that an increasing number of countries and regions are transitioning from deforestation to afforestation, raising hopes for a turning point for the world as a whole. The formula also considers the volume of timber, biomass and captured carbon within forest areas. The formula, known as “Forest Identity,” considers both area and the density of trees per hectare to determine the volume of a country’s “growing stock”, trees large enough to be considered timber. The researchers found that, amid widespread concerns about deforestation, growing stock has expanded over the past 15 years in 22 of the world’s 50 countries with most forest cover. In countries where per capita gross domestic product exceeds $4,600 (roughly equal to the GDP of Chile), richer is greener. In about half the most forested countries, biomass and carbon also expanded.
The researchers found that among the 50 nations studied, forest area in percentage terms shrank fastest from 1990 to 2005 in Nigeria and the Philippines, and expanded fastest in Vietnam, Spain and China. Indian forest area has slowly expanded since 1990. Growing stock fell fastest in Indonesia, Nigeria and the Philippines, and increased fastest in the Ukraine and Spain. In absolute terms, Indonesia and Brazil experienced the greatest losses of both forested square kilometers and cubic meters of growing stock while China and the USA achieved the greatest gains.
When forest transition occurs at a global level depends largely on Brazil and Indonesia, where huge areas of tropical forests are rapidly being cut and cleared. Encouragingly, in many other tropical areas, forests are re-growing. Studies in Central America show tree cover in El Salvador grew one-quarter from 1992 to 2001. Forests are also recovering fast in Puerto Rico and the Dominican Republic in harsh contrast to deforested Haiti, on the same Caribbean island. The main obstacles to forest transition are fast-growing poor populations who burn wood to cook, sell it for quick cash and clear forest for crops.
