Planting China's Great Green Wall

On the edge of China’s vast Gobi Desert, Wang Winji and his family are trying to fight desertification – with one tree at a time. Tree-planting has been at the heart of the government's environmental efforts for decades, but reforestation efforts have come under scrutiny this year after heavy sandstorms hit the capital of Beijing for the first time in six years. Rosanna Philpott reports.