Net Primary Productivity(NPP) has an increase of 170,658.11 t and the amount of Net Ecosystem Productivity(NEP) an increase of 44,355.94 t,in the project from 2002 to 2004 in Zhangye Prefecture.

• 通过三年的退耕还林(草)；能增加植物碳量累积(NPP)170 658.；11 t；NEP总量增加44 544