PLEA Network

4 September 2015, Climate News Network, Global tree census highlights need to restore forests. Mapping the density of forests reveals that there are far more trees on the planet than previously thought – but humans are destroying 15 billion a year.  An international collaboration of scientists has just completed the ultimate green census – by calculating that the planet is home to 3.04 trillion trees. The latest estimate is far higher and almost certainly more accurate than any previous attempt. But the bad news is that humans are removing trees at the rate of 15 billion a year – and there are now about half as many as there were at the dawn of civilisation. For every person on Earth, there are 422 trees – in total, more than 3,000 billion deciduous or evergreen growths with woody trunks greater than 10 centimetres at breast height. The researchers based their study on close analysis of satellite imagery, and of data from 429,775 plots of trees as measured on the ground in 50 countries on every continent except Antarctica. Statistical techniques. They counted forests in 14 “biomes” − or different kinds of climate, soil and topography − and in places not normally associated with trees, such as deserts, savannah, swamps, tundra and high mountains. They then they used statistical techniques that could extend their sample density measurements to the whole terrestrial world. The scientists report in Nature journal that the tropical and subtropical forests are home to 1.39 trillion trees, while the boreal forests of the north contain 0.74 trillion, and the temperate zones hold 0.61 trillion. Read More here