Tibet autonomous region began a series of helicopter flights on Monday to see if tree seeds can be effectively planted from the air. The tests, in Lhasa, are the first in the region.

Lhasa Xueying General Aviation Co handled the trial using two helicopters.

The region's forestry and grassland bureau said seeding by air is key to more effective greening because it is fast, cost-effective and not limited by terrain.

Seeds were dropped in areas including Lhasa's Chengguan, Dagtse and Liuwu districts and in the region's Gonggar and Dranang counties. The trial, using various types of aircraft, covered an area of 14,533 hectares with more than 119 tons of tree seeds, including sea-buckthorn and ailanthus.

Tibet has been redoubling its reforestation efforts in recent years. All villages and households at altitudes lower than 4,300 meters have been given trees that were previously without, and it has continued green landscaping work in the region's six river basins. The region's forest coverage rate now exceeds 12 percent.

Workers on Tuesday load bags of tree seeds onto a plane that will drop them in parts of Lhasa, Tibet autonomous region.