A large and growing number of countries are succeeding in reversing the longstanding trend toward deforestation, a surprising new analysis of the world's forests 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, one of the study's lead authors. The analysis was being published Tuesday in the Proceedings of the National Academy of Sciences.
Prepared by a team of researchers in Europe, the United States and Asia, the report offered a ray of hope after two weeks of ominous warnings about global warming. Forests act as pollution sinks, mitigating to some degree the effects of man-made carbon emissions.
It also suggested that downward environmental spirals could 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 be 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 Jesse Ausubel an environmental researcher at Rockefeller University in New York, who said that he personally had expected to live in a "skinhead" Earth by 2050.
Using new analytical techniques, the researchers calculated that the growing stock of forests had expanded over the past 15 years in 22 of the world's 50 countries with the most forest, and that many others were poised to make the transition from deforestation to reforestation in the coming decades.
In a few countries, notably Brazil and Indonesia, the destruction of forests remains a serious and worsening problem, the report found. Because of the cutting in these countries, the global trend is still negative.
Some experts reacted with caution to the results. The lack of good data on forests in many parts of the world meant it was 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 study had been provided by governments, which he said do not do a good job of measuring forests, or through 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," he said. "Is there a global paradigm change? We really don't know yet." He called for countries to undertake systematic forest inventories.
In many countries the reversal of deforestation over the past 15 years is partly the result of social changes that occur as countries develop and become wealthier, like the movement of rural dwellers to cities, the study said. A reduction in the number of people in the countryside decreases the cutting of trees and destruction of forests for things like heating and building, they said.
But in nations like China, India and Turkey, the shift also involved a strong measure of public policy, including restrictions on clear cutting, tree-planting campaigns and promotion of more efficient agriculture, which has meant that less land needed 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," Ausubel said.
The researchers analyzed new information on the world's forests from 1990 and 2005 that was recently released by the United Nations Food and Agriculture Organization, 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, biomass, the density of forest areas and the carbon-capturing capacity of trees.
The vast majority of the richer and more developed countries had more and denser forests in 2005 than they did in 1990. In the United States and in Western Europe, the transition began decades ago, but has increased rapidly in the past 15 years, the researchers found.
What was more encouraging the authors said, was that countries like Vietnam and Turkey seemed to have reversed the trend, along with giants like India and China.
But Holmgren cautioned that there were still problems in many parts of the world, where overlogging and poor forest management were rampant.
He added that the evidence for a reversal of deforestation remained weak in many nations. He noted, for example, that while China had indeed planted huge swaths of forest it was unclear whether 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."International Herald Tribune
