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.
1 The Oldest, Tallest, Widest and Biggest Trees in the World. 2  The Oldest Tree in the World: Old Tjikko (9,550 Years Old) 3  The Oldest Non-Clonal Tree in the World: Methuselah (4,845 Years Old) 4  The Tallest Tree in the World: Hyperion (115.6 meters/379' 4)