Ecology: Concepts and Applications 4th Edition by Manual Molles

Exercise 9

Kauffman and his colleagues (1993) estimated that burning the tropical forest at their study site resulted in the loss of approximately 21 kg per hectare of phosphorus. This quantity is about 11% to 17% of the total pool of phosphorus. If total annual inputs of phosphorus to the ecosystem, mainly by rain and "dry fall," amount to about 0.2 kg per hectare per year (Murphy and Lugo 1986), how long would it take these inputs to make up for a single agricultural burn such as that created by Kauffman and his colleagues? Assuming a constant rate of loss, how many burns would it take to totally exhaust existing supplies?