Afforestation and forests at the dryland edges: Lessons learned and future outlooks
In the Drylands of Northern China, such as the Loess Plateau region, a buffer zone of planted forests—a “Green Great Wall”—has been created in the last five decades. These government programs have often generated unintended environmental consequences, and have failed to achieve the desired benefits. Planted forests withhold erosion, dust storms and silting of streams but may reduce stream flow due to higher water use with serious consequences for water management. In spite of contrary expectations, afforestations improve regional climate conditions only insignificantly in the temperate zone. Cost-effective, ecologically useful forest policy in the Drylands requires the consideration of local conditions, and of alternatives such as restoration of grasslands and shrublands. The negative impact of expected rising temperatures on vitality and survival of forests needs to be taken into account as well.