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Forests disappearing since 2000? Google cloud maps global changes

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In this era of big data, anyone can now see how and where the world’s forests are changing thanks to a new mapping project made possible, in part, by the computing resources of the tech giant Google.

The map compiles 100-foot-resolution satellite images of Earth’s land area taken each season, every year between 2000 and 2012, to paint a picture of where tree’s were lost or gained.

Globally, the map shows that 888,000 square miles of forest were lost between 2000 and 2012. In the same period, 309,000 square miles were gained.

“We’ve been working on global-scale land cover monitoring for a while but just with big, blurry pixels. This is the first time we’ve done it with a resolution and granularity where change is quite discrete and we can quantify it clearly,” Matthew Hansen, a remote sensing scientist at the University of Maryland who  led the team that created of the map.

Since forest areas are logged or burned more or less all at once, but they grow back slowly over years or decades, areas of loss and gain are rarely in the same place in the time series, noted Hansen. Rather, the gains come in reforested lands that were cleared before 2000, or on abandoned agricultural land such as in Russia.

The map makes clear the location of working forests such as in the southeastern U.S., where 31 percent of the forest cover was either lost or regrown over the time series. Same goes for northern Europe.

“If you look at Finland and Sweden, it is patches of loss-gain, loss-gain, loss-gain, across the whole country, which is just IKEA on the landscape — it is a forestry culture,” Hansen said.