In response, the IUCN and local NGOs are working on a project to bolster Beijing’s water supplies, restore degraded forests and provide a solution that other megacities in China and around the world may follow.
The issue is urgent, as Beijing’s 21 million people are dependent on a water supply that’s only sufficient for 12 million people, according to the IUCN. The city draws the majority of its water from the Miyun Reservoir, a lake to the north and west. Occupying former farmland, the Miyun is fed from rivers and springs that wind down from the mountains.
Trees are notoriously important in mountains: their strong roots dig into hillsides and trap soil that would otherwise wander. The resulting matrix of dirt and plant material absorbs and filters water travelling the path of gravity, leading to more and cleaner water downstream. This process can mean the difference between taps that run and taps that don’t in water-stressed megacities.
Yet decades of logging and farming have left three quarters of the remaining trees on the mountains around Beijing in ‘sub-healthy’ or ‘unhealthy’ condition, according to the IUCN, resulting in ‘limited capacity for soil, water and biodiversity conservation’. In response, a programme of reforestation has been put in place.
A detailed study of where best to plant looked at 136 potential areas before settling on four key locations on ridge lines, hill slopes and river banks. A great emphasis was placed on consultation with local communities and authorities. ‘No restoration in China can be successful without the support of the government and the enthusiasm of local communities,’ said a spokesperson for the IUCN.
While the trees have still to grow to a height where they will be of benefit to water quality and supplies, the programme has now been disseminated to about 50 of China’s largest cities.