Agroforestry practiced on nearly half world's farms.

• Author: Block, Ben
• Position: EYE ON EARTH - Brief article

While farmers have long placed trees among their crops to enhance soil health, raise marketable fruits or nuts, and protect row crops from damaging winds, more farmers practice agroforestry than was previously appreciated, new data suggest.

According to a study from the Nairobi-based World Agroforestry Centre, nearly half of the world's farmlands have at least 10 percent tree cover, spanning more than 10 million square kilometers in total. Large areas of agroforestry exist in South America, sub-Saharan Africa, and Southeast Asia.

Previous efforts to quantify the extent of agroforestry struggled to differentiate between trees and crops in mixed stands. The recent study was unique, its authors said, because it used advanced satellite imagery to identify populated regions with arable land. The authors assumed that existing tree cover in these areas...