Washington, Aug 24 - Satellite imagery has revealed that there is significant tree cover in nearly half the farmed landscape worldwide, contrary to a belief that agriculture leads to massive deforestation.

It reveals that on more than one billion hectares -- which make up 46 percent of the world's farmlands and are home to more than half a billion people -- tree cover exceeds 10 percent. That includes 3.2 million sq km in South America, 1.9 million in sub-Saharan Africa and 1.3 million in Southeast Asia.

Scientists from the World Agroforestry Centre (WAC) using detailed satellite imagery have reported the discovery.

This is the first study to quantify the extent to which trees are a vital part of agricultural production in all regions of the world.

'The area revealed in this study is twice the size of the Amazon, and shows that farmers are protecting and planting trees spontaneously,' WAC Director General Dennis Garrity said.

'Trees are providing farmers with everything from carbon sequestration, to nuts and fruits, to windbreaks and erosion control, to fuel for heating and timber for housing,' he added.