When it comes to the state of forests on the planet, it may often seem like gloom and doom. Forest covers are being lost at alarming rates in many parts of the world from the island of Borneo in Southeast Asia to the Amazon region in South America. Yet a team of researchers in the US says that global tree cover hasn’t been shrinking, as is commonly believed. It’s been growing.
The researchers, who published their findings in the journal Nature and work for the University of Maryland, the State University of New York and NASA’s Goddard Space Flight Center, analyzed global satellite data to track the fluctuations in global forest cover over the past 35 years. Their data came from advanced high-resolution radiometers aboard a series of 16 weather satellites from between 1982 and 2016. This process enabled the researchers to detect small changes in forest cover globally.
“We show that — contrary to the prevailing view that forest area has declined globally — tree cover has increased by 2.24 million km2 (+7.1% relative to the 1982 level),” they write in their study. “This overall net gain is the result of a net loss in the tropics being outweighed by a net gain in the extratropics. Global bare ground cover has decreased by 1.16 million km2 (−3.1%), most notably in agricultural regions in Asia.”
Time to celebrate? Not necessarily. Plenty of virgin forests have been lost to agricultural development and logging. Taking their place have often been orchards and other marginally wooded areas. Yet these newly planted woods lack the ecological and biological diversity of those bygone old forests.
More encouragingly, however, most of the new tree cover has sprouted in previously barren areas such as deserts, tundra landscapes, on mountainsides, in cities and in other non-vegetated land. Warmer temperatures brought on by climate change have allowed timberlines to creep up higher in some mountainous regions and forests to take roots in some tundra areas.
New trees have also grown substantially on large plots of farmland that have been abandoned in countries like the US and Russia. Reforestation efforts by people worldwide have also made an impact. Overall, some 60% of new forest cover growth can be attributed to human activities.