In the 1810, a remarkable transition happened in Denmark: Forests ceased shrinking and began to expand. The turnaround was driven by several factors, such as migration of people to cities and the abandonment of less fertile fields. Forest area subsequently began to recover in the rest of Europe and the United States. Now, an analysis of global forest data suggests that forests are returning in more and more countries, which leads the authors to predict that the volume of wood in the world's forests will likely stabilize in the coming decades.
The data come from the United Nations Food and Agriculture Organization, which last year released a report on the trends in forests from 229 countries between 1990 and 2005. An international group of researchers led by forest ecologist Pekka Kauppi of the University of Helsinki, Finland, dug into the numbers. In a novel approach, the researchers compared trends in both forest area and forest density for the 50 most-forested nations.
Deforestation is going on in about half of these countries. It's most rampant in Brazil and Indonesia, where some forests shrank, primarily as some were cut down to make room for agriculture, and others became less dense as they were logged. Indonesian forests were logged the heaviest, becoming 4% less dense each year, the team reports today in the Proceedings of the National Academy of Sciences. Yet in 22 of the countries, forests are expanding and becoming more dense. The top countries were Spain, Vietnam, and China, which has had a major program to plant trees. Another highly populated country, India, has stabilized its forests.
Two of the most important reasons are declines in agricultural area and the expansion of tree farms, although switching from cutting to importing wood also plays a role. Currently, about one third of harvested wood comes from industrial plantations. Kauppi and his colleagues predict that this will rise to three-quarters by 2050. That could reduce the pressure on natural forests, they say, although they did not look at biodiversity in their analysis. In another 2 to 4 decades, almost the all the major forested countries will have increasing forests. "The end of deforestation may be in sight," says author Jesse Ausubel, an environmental scientist at Rockefeller University in New York City.
"They found a surprisingly positive trend," Gary Hartshorn, a tropical forest ecologist with the World Forestry Center in Portland, Oregon. He agrees that improving forestry can help save wild forests. "If that trend continues, it will be very positive." But Janet Ranganathan of the World Resources Institute in Washington, D.C., notes that the self-reported data are patchy and sometimes unreliable, so she cautions that it's too soon to predict an end to deforestation.