Carbon Storage And Carbon Sequestration Of Casuarina Equisetifolia Plantation On Coastal Sandy

The forest is the main body of biosphere. The carbon cycle of forest ecosystems plays an important role in the global carbon cycle, which is related to CO₂ concentration in atmosphere and has an obvious effect on composition of atmospheric elements. To improve the estimation accuracy of forest ecosystem carbon cycle would help forecast the change of climate in the future .At present the man-made forest area in China come to be more than 53 million hectares, being number one in the world but there are few data on the carbo n cycle of forest plantation ecosystem in the China South, which is the major zone of forest plantation in China ,limiting the exact estimation on the carbon sink or source of the man-made forest ecosystem in the South of China, and the function of the adjustment on the climate. Such as the study on an important tree of protection forest in coast zone called Casuarina equisetifolia was not researched yet .So the forest plantation in Fujian has been study on the carbon storage, and carbon balance to provide the reference on the carbon cycle on the forest plantation in China South. The results were showed as follows:1 There were differences among carbon content of different growing stage of pure forest of Casuarina equisetifolia and the mixed forest of Pinus elliottii and Casuarina equisetifolia at 15-year-old and the mixed forest of Acasia crassicarpa and Casuarina equisetifolia at 10-year-old in tree organs(leaf, branch, stem, bark and root),litter layer .There were differences among the carbon content of the tree different organs, moreover the sequence of organs varied in different age and stand types. The soil carbon increased of depth in all stand types.and the maximum differences of soil carbon content for adjacent soil layer occurred at the 0～20cm and 20～40cm soil layer.2 The carbon storage of Casuarina equisetifolia plantation ecosystems increased with the increase of age and the sequence of carbon storage of Casuarina equisetifolia for the different growing stages was MP(mature plantation)222．69t·hm^-2 >MAP(middle-aged plantation) 164．11t·hn^-2 > YP(young plantation) (76．80t·hm^-2 )and the carbon storage of latter layer were also show the consistent orderlineness. Soil carbon storage was the main carbon pool of the forest ecosystem, showing a generally increasing age but the proportion of total carbon storage showing a generally decreasing trend with increasing age ,but the reverse was the tree .which was the main body of the difference among carbon storage of different growing stages, but the difference amo ng three forest types were caused by the cooperation of soil and tree. The litter carbon storage possessed little carbon storage possessed little proportion of ecosystem carbon storage, but being link pooling connecting generation and soil, the litter produced important on the forest ecosystem.3 Based on the data of annual net production and relevant carbon content ,the annual carbon net fixation of different growing stage (Young plantation, Middle-aged plantation, Mature-plantation.) of Casuarina equisetifolia was 10．974t·hm^-2·a^-1,14．889t·hm^-2·a^-1 and 8．457t·hm^-2·a^-1 , respectively, showing that MAP(middle-aged plantation)>YP(young plantation)>MP (mature plantation) caused by the difference of the annual net fixation of tree and litter.4 A study was carried out to determine the production component and mensal dynamics and seasonal dynamics of carbon content of litterfall to different growing stage of Casuarina equisetifolia.The results were showed that in different growing stage respectively about YP (young plantation)4．84t·hm^-2,MAP (middle-aged plantation) 9．25t·hm^-2 MP(mature plantation) 13．33 t·hm^-2 litter production was returned to the plantation soil., in which79．97 %～91．94 %, 2．89%～16．65%, 3．38%～6．27%were occupied by leaves, branches and Cone . Total litter production changed obviously in different growing stage .Litter production in mature plantation were 2．75 times as higher as young plantation and monthly litter production averagely peaked in from July to September with the highest in September ,The carbon content of litter changed in the order of winter>autumn>summer>spring. The C return through litterfall were mainly influenced by the litter production, it showed that the same dynamics as the litter production.