Earth’s tress number 3 trillion according to a tree count carried out by Dr Thomas Crowther and a team from Yale University, who combined a mass of ground survey data with satellite pictures. That’s roughly 420 tress for every person on the planet. The team estimates that we are removing about 15 billion trees a year, with perhaps only 5 billion being planted back.
Crowther and his colleagues merged these approaches by first gathering data for every continent except Antarctica from various existing ground-based counts covering about 430,000 hectares. These counts allowed them to improve tree-density estimates from satellite imagery. Then the researchers applied those density estimates to areas that lack good ground inventories. For example, survey data from forests in Canada and northern Europe were used to revise estimates from satellite imagery for similar forests in remote parts of Russia.
The highest tree densities, calculated in stems per hectare, were found in the boreal forests of North America, Scandinavia and Russia. These forests are typically tightly packed with skinny conifers and hold roughly 750 billion trees, 24% of the global total. Tropical and subtropical forests, with the greatest area of forested land, are home to 1.3 trillion trees, or 43% of the total.
Picture Credit : Google
