Study On Carbon Sink And Potential Of Forestry Activities In China

With the increased greenhouse effective and climate warming recent years, forest carbon sink is payed more and more attention by the world. The most popularly concerned topic by the international society is how to get biggest mitigation effect under the smallest economy cost. In the every endeavor to mitigate the global change, forest activities have very important and irreplaceable position and role. The article 3.3 and 3.4 of Kyoto Protocol signed in 1997 regulate that greenhouse gas emission or removal caused by the human activities such as afforestation, reafforestation, deforestation, forest management, farmland management and vegetation restoration and so on can be used to offset the greenhouse gas emission goal that annex I countries promised through the appropriate way. But the emission reduced or sink cleared caused by these activities must be transparent, measured and verified. It requests to scientificly evaluate and monitor the emission reduced and sink cleared caused by these activities. Forest carbon sink produced by the forestry activities is a better choice to slow down the greenhouse gas increasement in the atmosphere. So international society, governments and scientists all pay attention to the study on the carbon accounting of forestry activities.Under the framework of IPCC Guidance, the paper evaluates and predicts the carbon sink and its potential of the main forestry activities (afforestation, reafforestation, deforestation, forest management) in china at the country scale, and confirm the hot spot of the china forestry activities carbon sequestration. It can provide data support for china to offset part of greenhouse gas emission because of the quick economy development in the future, and technical support for the site choice to develop forest carbon sink projects. Using the chance of the international carbon trade at present, forestry department also can induce the foreign fund and technology to gain the further development. The results show that,1) Annual carbon stock change of afforestation and reafforestation in China shows rapid increasement trend before 2020, and remain about 100 MtC.a-1 after 2020. The earlier is the baseline, the bigger is carbon sink potential of afforestation and reafforestation. The gap becomes smaller after 2020. It means that the choice of baseline year has a small effect on the carbon sink of affforestation and reafforestation after 2020. Afforestation and reafforestation together absorb 10.89×10~9tC between 1990 and 2009, of which biomass absorb 8.18×10~9tC and soil aborb 2.71×10~9tC.2) Carbon absorbsion in afforestation and reafforestation is mainly man-made afforestation, which is about 90% of total carbon absorbsion. And afforestation from air-boern is about 10%. When 1990 is baseline year, before 2010 carbon absorbsion of man-made afforestation is mainly from cash forest and forest for timber. Carbon absorbsion of forest for protection rapidly increase after 2010, become the main source of man-made afforestation, followed by the forest for timber, cash forest and bamboo. The carbon absorbsion potentional of forest for fire is smaller. When baseline is 2000, forest for protection is the main carbon sink and is about twice of other forest, followed bu the forest for timber, cash forest, bamboo and forest for fire.3) The carbon sink potential of afforestation and reafforestation in Southwest region of China is parently bigger than that of the other regions, followed by the East and South of China, Northwest, North of China and Northeast region. The potential in Xizang is very small. It can provide support for our site choice of forest carbon sink project development.4) When baseline year is 1990, carbon emission from deforestation shows quick increasement trend before 2002, then declines afterward. When the baseline year is 2000, carbon emission from deforestation increase rapidly before 2003, then decline slowly. The later is the baseline year, the bigger is the carbon emission from deforestation. Soil carbon emission caused by the deforestation is bigger than the biomass carbon emission during deforestation. Carbon emission from deforestation is totally 6.19×109tC, of which biomass emit 2.94×109tC and is about 44% of deforestation total emission. And soil emit 3.25×109tC, is about 55%.5) Carbon sink change trend from forest management are the same under the gross-net and net-net at the same baseline year. But the carbon sink amount is bigger under the gross-net than that under the net-net. The earlier is the baseline year, and the smaller is the area of forest management, the smaller of the carbon sink potential under the gross-net. Under net-net, the earlier is the baseline, the higher is the carbon sink potential of the forest management. The difference of the baseline year choice has a bigger affect on the carbon accounting of forest management.6)Combined with the afforestation and reafforestation, deforestation, closing hillsides to facilitate afforestation and forest management, the accounting results show that total carbon sink potential trend of forest activities in China increase rapidly from baseline year to 2020 and then slow down. Under gross-net, forest activities always are carbon sink from beginning, and carbon sink is bigger in 2020 when baseline is 1990 than that when baseline is 2000. The carbon sink almost are the same after 2020 under two baselines. Under net-net, the total carbon accounting of Chinese forest activities shows carbon source at the first 2-3 years after baseline, then changes to net carbon sink. And the carbon sink amount is bigger when baseline is 1990 than the amount when baseline is 2000.7)Carbon sink of forest activities come mainly from tree growth. But if deforestation happens, it will have a huge affect on the soil carbon.We find that the carbon sink from afforestation and reafforestation, forest management is huge and can satisfy the need of climate change negotiations of our country to the certain. And this is the same as the forest promise of china for 2020 at the same time. It can finish our forest carbon sink task under"413"goal. But we also need to realise that some facors needed by the study meathod come mainly from liberations collection and Chinese inventory of forest resource. It has an impact on the precision of the study result. We need to further carefully study the factors in the accounting method in the next step, reduce the uncertainty of accounting results, and provide technical support for drawing up the forest carbon sink sustainable development policy of China.