Biomass And Carbon Storage In Poplar Plantations In The North Of JiangSu Province

Biomass and carbon storage in poplar plantations over 10 years were evaluated at the SiYang County, SuQian City, JiangSu Province. Experimental treatments applied in a split-plot design included 8 poplar clones (S3804,S372,S3239,ST1,S3801,S3201,S3261,ST2),6 plantation densities of 2 age groups (4a:693,333,476 stems·hm-2 ;6a:168,333,460 stems·hm-2)and 4 age groups(4,6,8,10a) .Based on the regression model of total biomass production developed, biomass and carbon storage in different plantations were estimated as well as total carbon storage of SuQian City. Some basis data and results have been also made useful for choosing clones and forestry management. Some main conclusions were as follows:(1)The ranking of the plantation biomass and carbon storage by different clones was S3804>S372> S3239> ST1> S3801> S3201> S3261> ST2, the carbon storage of S3804 was 44.482 t·hm-2, 46.74%,55.78%more than S3201, S3261 respectively and two times as that of ST2. The annual increment of carbon storage over10 years differed significantly from 1a to 6a(ρ<0.05), but no significant difference was observed from age 7 to 10.The similar carbon storage distribution of tissues in different age groups was concluded despite of significant difference of their absolute value (ρ<0.05).(2)The biomass and carbon storage per stem of plantations decreased as the density increased. The carbon storage by planting density was 693>476>333stems·hm-2,460>333>168stems·hm-2,and by tissues was stem>root>branch>leaf for all plantations . The average carbon concentration ranged from 41.14% to 52.37%, its distribution by components was stem> branch>root> leaf except for 460 stems·hm-2 which was stem> root> branch> leaf.(3)The biomass production and carbon storage in different age plantations increased while the age increased. The carbon storage in 4,6,8,10a plantations was 6.436,17.447,39.133,52.450 t·hm-2 respectively. The carbon concentration in various organs as well as the same organ in different age plantations differed significantly ranged from 36.2% to 48.6%(ρ<0.05).The soil C,N storages decreased rapidly during 4~6a, then increased gradually, from 52.37,57.77 t·hm-2 to 58.84,67.47 t·hm-2 respectively.(4)The carbon storage of poplar plantations in SuQian City was 14.142 million t, and the mean carbon densities of plantation, tree and soil were 91.973, 19.829, 69.156 t·hm-2 respectively.