Carbon Storage Of Forest Vegetation And Spatial Distribution In Sichuan Province

It is important to study the carbon storage and carbon cycle of forest vegetation in the global carbon cycle and climate change. Forests in Sichuan province is a principal part of the southwestern forested areas, the second biggest in China, which is sensitive to globe climate change and also contribute to approach. However, very few reports can be referred in ecosystem carbon storage, dynamic variety and atmosphere CO₂ density. The biomass models were built and the carbon content rates were investigated in different forest types. Then the forest carbon storage in Sichuan province was estimated based on the data from forest resource inventory collected by county in 2004 and its spatial distribution was studied.(1) The carbon content rates in branches, leaves, stems, barks and roots of 22 kind of main tree species in Sichuan were investigated and variance analysis. The analysis result revealed that organs'carbon content rates ranged from 0.4261～0.5708. The organs'carbon content rates of the same species vary significantly between different organs except Pinus armandii Franch. The organs average carbon content rates can not stand for the carbon content rates of the forest but the carbon content rate in stand weighted by biomass. The carbon content rates of thirteen conifer species stands were measured as 0.5259 in Larix masteriana, 0.5262 in Pinus taeda., O.5437 in Pinus armandii Franch, O.5144 in Pinus massoniana, O.5216 in Pinus elliottii, O.5281 in Pinus yunnanensis, O.5314 in Pinus tabulaeformis, O.5211 in Cupressus funebris, O.5365 in Cunninghamia lanceolata, O.5479 in Cryptomeria fortunei, O.5489 in Metasequoia glyptostro boides, O.5050 in Abies georgei and 0.5160 in Picea aspoerata. Those of the nine broadleaved species stands were measured as 0.4956 in populus, O.5041 in Liquidambar formosana, O.4938 Betula spp, O.5019 in Eucalyptus grandis, O.4832 in Quercus spp, O.5005 in Alnus cremastogyne, O.4675 in Cyclobalanopsis glauca, O.5050 in Mochilus nanmuand 0.4914 in Cinnamomurn camphora. As a result, the carbon content rates in different organs or in stand weighted by biomass of conifer stands were higher than those of the broadleaved stands.(2) Data of biomass by field survey were used to build the biomass model as W=aV^b. The carbon storage and density of forest vegetation in Sichuan Province were estimated based on the data from forest resource inventory collected by county in 2004. Using the carbon content rates, the result for the carbon storage and carbon density of forest vegetation in Sichuan accounted for 549.5043Tg and 27.73t/hm². The carbon storage varies in different vegetation, was 478.2522Tg in timber forests, 62.3825Tg in shrubberies, in economic forests was 5.3682Tg and 3.5014Tg in bamboo forests. The carbon density was 38.04 t/hrn² in timber forests, 9.88 t/hm²in shrubberies, 11.85 t/hm² in economic forests and 7.31 t/hm² in bamboo forests. The carbon storage in timber forests dominates in Sichuan. The carbon storage was mainly in natural stand, accounted for 86.1%. The carbon storage in mature stand and overmature stand was dominate, accounted for 30.2% and 35.7% respectively. The carbon density of forest vegetation was in inverse proportion to population density (y＝-3.2204Ln(x) + 40.654). The climate impact to the distribution of forest carbon density was nearly enshrouded by human's activity.(3) The database was established based on the forest carbon densities. The forest carbon density map was made by geographic information system. The forest carbon density in the west was higher than that in the east. Special distribution in altitude: the forest Carbon storage and density were both subject to normal distribution and mainly distributed on 3000-4000m. Special distribution in slope: the forest carbon storage was subject to normal distribution and mainly distributed on steep slope. The forest carbon density increased following the accretion of slope mainly distributed on dangerous slope. The forest carbon storage in shaded slope or half-shaded slope was a little higher than in sunny slope or half-sunny slope.(4) The forest carbon densities distribution was consistent as forest vegetation. The forest carbon density distribution in Sichuan can be divided into three forest zones based on forest types, carbon density and physiognomy, as the evergreen broad-leaved forest zone in the Basin and on the marginal mountainous areas, the subalpine dark conifer forest zone in western Sichuan and the plateau shrubbery, and meadow and grassland zone in the northwest of Sichuan. Practicable countermeasures should be taken to improve and stabilitate forest carbon fixation in various forest areas.