Conditions that promote karst development are well-jointed, dense limestone near the surface; a moderate to heavy rainfall; and good groundwater circulation. Limestone (calcium carbonate) dissolves relatively easily in slightly acidic water, which occurs widely in nature.
Crowther said first he had to figure out how many trees are on Earth and that number was far more than anyone expected: 3.04 trillion trees, according to a study published Wednesday in the journal Nature. 14 Photos Trees Around The World.
2. Right now, one mature leafy tree produces enough oxygen for the lifetime of ten people each season! There are 400 billion trees, 6.7 billion people on Earth â every person has 60 trees.If you did the math, how much oxygen do you think we'd have if there were no trees at ALL?. Right now, one mature leafy tree produces enough oxygen for the lifetime of ten people each season! There are 400 billion trees, 6.7 billion people on Earth â every person has 60 trees.