Study On The Growth Law And The Carbon Storage Of The Main Afforestation Tree Species On The Muddy Sea-coast In Jiangsu Province

This paper was taking the Populus tomentosa Carr, Metasequoia glyptostroboides Hu et Cheng and Ginkgo biloba L as the research object, which were the main afforestation tree species on the muddy sea-coast in Jiangsu province .According to the investigation of the sample plot,cut down 17 standard trees and weighed each organ biomass, determined their carbon content after drying. cut off the rings and analyzed the trunk, Collected the litter in the sample plot.(1) The fast growing period of Populus was in 6 to 11 years, earlier than Metasequoia glyptostroboides which was in 16 to21 years, and Ginkgo was the late-growth specie, keeping on fast growing after 50 year. Populus and Ginkgo were wide-crown species, and Metasequoia glyptostroboides is narrow-crown specie. The trunk accounted more than 50% in the tree biomass, and the root accounted for 20%.(2) The biomass of the different root level was increasing with age raised,and its tendency was similar with the aboveground biomass,which showed "S"pattern. The gap of the biomass in the each root level were little in the young age, and enlarged when they were got older. root system of the Populus was more development than the Metasequoia glyptostroboides,but fine root was reversing.(3) The density of the basis was bigger than top, which was declining with the vertical position increasing; The stem density was raising with age increasing, rapidly in the young age, and the tendency would slow down after the mature age;the stem density of the Metasequoia glyptostroboides (21a) was bigger than Poplar (19a),which's uniform is better than Poplar also.(4) The fall tendency of those trees showed the normal distribution, largely in the middle time and rarely in the beginning and end. The fall time of Metasequoia glyptostroboides was lagged to Poplar and Ginkgo,which appearance of fall time lagged 40 days and the end of fall time lagged 20 days.(5) The water content of leaf was in the first level, stem and root was in the second level, branch and bark was in the third level,and it was a large gap of the water content in the each level. The carbon of those trees accounted for 42% of the dry weight,which accounted for 25%-27% of the fresh weight to Poplar and 19%-22% to Metasequoia glyptostroboides. The carbon of each different organs accounted for 41% - 51% to Poplar and 38% - 46% to Metasequoia glyptostroboides.