The Grain for Green Project (GGP),one of the most ambitious ecological projects to be launched in China,was
aimed at converting low-yield slope cropland,barren hills,and wasteland into grassland and woodland. The objective of
this study was to calculate the carbon stock changes and carbon sequestration potential of the GGP in Western Henan under
cutting and no-cutting scenarios,in order to develop a method for further estimation of the carbon sequestration potential of
the national GGP and produce a scientific reference for the ecological system management of the GGP in the long run. The
Western Henan,one of the major districts that implemented the GGP in China,initiated the GGP in 2002. We analyzed
Songxian,which is a major county in terms of implementation of the GGP in Western Henan,as a case to evaluate carbon
storage and the carbon sequestration potential under cutting and no-cutting scenarios. We collected data on each year from
2002 to 2010,such as tree species,the planted area of the project in Songxian,the use of a growth curve suitable for
China's planting volume,the findings about the soil organic carbon changes after the GGP together with biomass density of various species,carbon content,the biomass expansion factor,and the estimated carbon storage and annual carbon
sequestration for the GGP from 2002 to 2050. The results showed that total carbon storage was 0.470 Tg in 2010,when the
project was completed. Total carbon sequestration in the former period is larger than that in the latter period during the
project's implementation. The annual carbon sequestration of the soil organic-carbon pool was negative and released carbon
from 2002 to 2010,then an increase in the annual carbon sequestration of soil organic-carbon pool was observed,along with
net carbon gains after 2011; the project' s annual carbon sequestration peaked in 2015 under no-cutting and cutting
scenarios. The annual carbon sequestration under the cutting scenario is greater than that under the no-cutting scenario after
2033. The potential increment of the carbon sink of the GGP-covered Songxian will reach 0.760,1.464,1.852,and 1.985
Tg by the year 2020,2030,2040,and 2050 under the no-cutting scenario; it will reach 0.760,1.240,1.657,and 2.000
Tg under the cutting scenario. The potential increment of the carbon sink under the cutting scenario will exceed that of the
no-cutting scenario after 2050. In the long run,the GGP in Western Henan has a greater carbon sequestration potential
under the cutting scenario than that under the no-cutting scenario. Our results suggest that moderate forest harvesting for the
GGP can increase the capacity for carbon sequestration.
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