Carbon Storage And Carbon Sequestration Rate Of The Main Vegetation Types In Liupan Mountain

As the largest terrestrial carbon pool, the aboveground and soil carbon stock of forestecosystem occupies respectively80%and70%of the global carbon stock. Forests play animportant role in regulating the global carbon balance and mitigating the rise inatmospheric greenhouse gas concentration. There are many researches about carbonstorage of the forest ecosystem. Due to differences in the research scale and methods, thereare uncertainty and complexity in carbon storage of the forest ecosystem. To reduce theuncertainty in estimation of carbon sequestration and the error of model simulation results,it is necessary to accurately quantify the carbon stocks of regional forest ecosystem,sequestration capacity and the distribution. Four typical forests in Liupan Mountain wereselected in this study: they are Larix principis-rupprechtii （plantation）, Pinustabulaeformis （plantation）, Pinus armandi （natural forest） and Quercus wutaishanica（natural forest）. We studied biomass and carbon storage in these forest systems by fieldinvestigation and laboratory analysis. In addition, we explored the dynamic changes ofcarbon sequestration ability of vegetation through analyzing the growth process ofplantations. In order to provide information of the hydro-ecological function of forest litter,the litter water-holding characteristics are discussed in this paper. Main findings are asfollowing:（1） Vegetation and litter carbon storage was29.87t·hm^-2（Larix principis-rupprechtii）,58.06t·hm^-2（Pinus tabulaeformis）,48.5t·hm^-2（Pinus armandi） and43.95t·hm^-2（Quercus wutaishanica）, respectively. In spatial distribution, the vegetation carbon storagefollowed the order tree layer> litter layer> shrub layer> herb layer. The soil organiccarbon concentration decreased with depth increasing. Pinus tabulaeformis had the lowestsoil carbon storage (109.25t·hm^-2), and the mean value of other three forests was184.50t·hm^-2. The carbon storage of forest ecosystem was216.85t·hm^-2,167.31t·hm^-2,223.58 t·hm^-2and235.26t·hm^-2in the four tested forests. The distributions of carbon stock werefollowed as: soil layer> vegetation layer> litter layer, indicating that soil carbon pool isthe key part of forest ecosystem and plays a vital role in the forest carbon cycle.（2） The annual DBH increments of the dominant, average and suppressed treesshowed a consistent trend within the two tree species of Larix principis-rupprechtii andPinus tabulaeformis. Their growth began to decline at12thand10thyears whenintermediate thinning would be taken. With the average volume of0.074m³and0.070m3,29a Larix principis-rupprechtii and30a Pinus tabulaeformis have not yet reached thematuration stage. We predict the mature age of Larix principis-rupprechtii is30a andPinus tabulaeformis is35a. The volume growth of the two plantations can be simulated byquadratic polynomial equations with R2>0.98. From the12thyear, the carbonsequestration rate of Larix principis-rupprechtii tended to be a stable level of2.70t·hm^-2·a^-1. The Pinus tabulaeformis, however, grew slowly in the early stage, and theaccumulation of carbon increased rapidly during18th-26thyear (4.32t·hm^-2·a^-1), thendecreased with times increasing.（3） The amount of litters in the four forests was12.05²6.40t·hm^-2with thickness of1.0⁴.5cm. Litter stock （g） and thickness （cm） of Larix principis-rupprechtii forests had alinear correlation （y=36.64+72.12x，R²=0.65）. There was no significant correlation inother three stands. Water immersion method had been applied to determine the variation ofwater-hold rate （%） with times （h） among different vegetation types. The regressionequation between water-hold rate and time were y=alnx+b. The modified interceptionwas4.31mm,1.40mm,4.13mm and1.39mm respectively, indicating that Larixprincipis-rupprechtii and Pinus armandi had relatively higher water-holding ability.