"From the new data, it seems possible that we could reverse a global trend that many people thought was irreversible," said one of the lead authors, Pekka Kauppi of the University of Helsinki.
The scientists analyzed information from national databases and the United Nations Food and Agriculture Organiziation and calculated that the forests had expanded in 22 of the 50 most forested countries during the past 15 years. They added that many of the remaining 28 were also close to switching from deforestation to reforestation in the next few decades. Brazil and Indonesia still had serious problems with deforestation, and the cutting in these countries means that the global trend is still leaning toward deforestation overall.
The report attributed the reversal trend partly to social changes resulting from countries developing and becoming wealthier, rural families moving to cities, for example. As fewer people live in the country, fewer trees are used for things like heat and buildings, the report said. In countries such as China, India and Turkey, a lot of credit for the change was given to strong public policies such as tree-planting campaigns, promotion of efficient agriculture practices, and restrictions on clear cutting.
"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," said Jesse Ausubel, an environmental researcher at Rockefeller University in New York.
The research team was comprised of scientists in Europe, the United States and Asia, and reported that the reversal of deforestation was good news in the face of growing concern about global warming, as forests tend to act as pollution sinks and partially alleviate man-made carbon dioxide emissions.
The report also suggested that a combination of new policies and some luck could reverse other worsening environmental issues, since 20 years ago reversing deforestation was considered impossible.
"This is the first time we have documented that many countries have turned the corner; that gradually forests are coming back," Ausubel said, adding that, before the study, he had personally expected to live in a "skinhead" Earth by the year 2050.
Peter Holmgren, chief of Forest Resources Development at the United Nations Food and Agriculture Organization in Rome, said it was hard to be confident about the report. He noted that there was a lack of data on forests in many part of the world and governments, which have a generally poor track record when it comes to measuring forests, had provided much of the data in the study.
"There are trends that these guys have observed that seem true but it's difficult to state for certain," Holmgren said. "Is there a global paradigm change? We really don't know yet."
Holmgren added that countries around the world should start systematic forest inventories.
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