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 China's environmental efforts for decades as the country seeks to turn barren deserts and marshes near its borders into farmland and screen the capital Beijing from sands blowing in from the Gobi, a 500,000 square-mile expanse stretching from Mongolia to northwest China, which would coat Tiananmen Square in dust nearly every spring.

But in March, heavy sandstorms hit Beijing for the first time in six years, putting the country's reforestation efforts under scrutiny, with land increasingly scarce and trees no longer able to offset the impact of climate change.