14 November 2006Elisabeth Rosenthal
A large and growing number of countries are reversing the longstanding trend toward destruction of their forests, a surprising new analysis has found.
“From the new data it seems possible that we could reverse a global trend that many people thought was irreversible,” said Pekka Kauppi of the University of Helsinki in Finland, a lead author of the study, which appears today in The Proceedings of the National Academy of Sciences.
The report, by a team of researchers in Europe, the United States and Asia, is a ray of hope at a time of ominous environmental warnings about global warming caused by man-made carbon emissions. Forests can act as pollution sinks, easing the emissions’ effects to some degree.
The scientists say their study suggests that environmental damage can be reversed with a combination of policy and luck. Twenty years ago most scientists believed that deforestation was an inexorable result of industrialization and that the earth would soon be virtually denuded of trees.
“This is the first time we have documented that many countries have turned the corner, that gradually forests are coming back,” said one of the authors, Jesse Ausubel of Rockefeller University in New York, who added that he personally had expected to live in a “skinhead” earth by 2050.
But some experts reacted with caution to the results. The lack of good data on forests in many parts of the world means that it is hard to be confident about the study’s “positive indications of an important change,” said Peter Holmgren, chief of forest resources development at the United Nations Food and Agriculture Organization in Rome.
He noted that much of the data for the new study was provided by governments, which he says do not do a good job of measuring forests, or by aerial surveillance, which is notoriously unreliable.
“There are trends that these guys have observed that seem true, but it’s difficult to state for certain,” Mr. Holmgren said. “Is there a global paradigm change? We really don’t know yet.” He called for countries to undertake systematic forest inventories.
The report acknowledges that in a few countries, notably Brazil and Indonesia, the destruction of forests remains a serious and worsening problem. Because of the continuing cutting in those countries, the global trend is still negative.
Yet the researchers, using new analytical techniques, calculated that in the last 15 years forests had actually expanded in 22 of the 50 countries with the most forest, and that many others were poised to make the transition from deforestation to reforestation in the coming decades.
The reversal is partly a result of social changes that occur as countries develop and become wealthier, the study said. For example, as rural dwellers move to the cities there are fewer people in the countryside to cut down trees for uses like heating and building.
But in nations like China, India and Turkey the shift also involved a strong measure of public policy, including tree-planting campaigns, restrictions on clear-cutting and more efficient agricultural practices, which means that less land needs to be cleared for growing food.
“On a global level, deforestation will be reversed if we maintain this trend, which has involved a lot of different factors: a shift to highly productive agriculture in some places, as well as people like you and me reading newspapers on the Internet so that forest is not destroyed,” Dr. Ausubel said.
The researchers analyzed new information from the Food and Agriculture Organization on the world’s forests from 1990 and 2005, as well as the contents of national databases.
Instead of merely estimating the area of forest in each part of the world, they developed new research tools that took into account the volume of timber, the amount of biomass, the density of forest areas and the carbon-capturing capacity of local trees.
A vast majority of the richer and more developed countries had more forest area and denser forests in 2005 than in 1990. In the United States and Western Europe the transition began decades ago, but it has increased rapidly in the last 15 years, the researchers found.
More encouraging, the authors said, countries like Vietnam and Turkey seem to have reversed the trend, as have giants like India and China.
But Dr. Holmgren cautioned that there were still many problems in many parts of the world, where overcutting and poor forest management are rampant.
He added that the evidence for a reversal of deforestation remained weak in many nations. He noted, for example, that while China had planted huge swaths of forest, it was unclear if these were sustainable.
“Are people in northern Thailand moving off of marginal farmland and going to Bangkok so the land can revert to forest?” he asked. “It’s a scenario, but I’m not sure we really know that.”
http://www.nytimes.com/2006/11/14/world/14forest.html?_r=1&oref=slogin
