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.
As the largest plant on earth, the tree has been a major source of stimulation to the mythic imagination. Trees have been invested in all cultures with a dignity unique to their own nature, and tree cults, in which a single tree or a grove of trees is worshipped, have flourished at different times almost everywhere. Even today there are sacred woods in India and Japan, just as there were in pre-Christian Europe.