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.
How many acres of land are in the world? The land are of the earth is about 148,940,000 kmÂ² , or about 57,491,000 mi2 or about 36,794,240,000 acres. Wikipedia has more information, and a link is provided.