Population Structure And Carbon Sequestration Evaluation Of Tamarix Chinensis In The Tarim River

Tarim River basin is located in the hinterland of Taklimakan desert where droughty and windy climate,water shortage,slowly speed of soil formation,sparsely vegetation,lower biodiversity and simple structure of food chain.Tamarix chinensis a psammophyte which is widely distributed in arid and semiarid region has draw people's attention with its unique biological and ecological characteristics and important ecological,social,and economic values.Based on the investigation of status of tamarisk population,the population structure and distribution pattern,biomass and carbon sequestration ability of T.chinensis in the sandy land,saline land and Gebi desert were studied in the Tarim River basin.The aims to evaluate the service function of carbon sequestration of tamarisk forest ecosystem,which will help enhance people a correct understanding of the ecological value of Tamarix chinensis.The results showed that:(1)There were 8 families,9 genus and 9 species in bushwood of dominant species of T.chinensis associated with some kinds of desert shrubs and herbs in three site conditions.The order of Shannon Wiener diversity index,Simpson index and Pielou evenness index was sandy land > Gebi desert > saline land.(2)The diameter class structure of T.chinensis population was unimodal in three kinds of site conditions.But,there was more intact structure in sandy land than saline land and Gebi desert with its diameter mostly were ?and III class.With the increase of height level,the change of the number of individuals in different height class was same to the diameter class which showed a unimodal type in sandy land,but declined in the saline land,and increased in the Gebi land.(3)With increasing of land coverage,the number of small individuals increased significantly in the sandy land.This indicated that high land coverage prevented the sand flow and soil erosion effectively,which offered good habitat for survival and growth of T.chinensis.Especially to the increasing the number of small diameter class(?)and proportion can ensured the sustainable development of the population.(4)In the G1 coverage conditions,with the increasing of diameter class,the population mortality of T.chinensis in the sandy land and Gebi desert changed from low to high and then to low,but descreased in the saline land.And population mortality both in sandy land and Gebi desert were significantly higher than that in the saline land.In the sandy land conditions,the population mortality of T.chinensis in G2 coverage was significantly higher than that of G1 and G3.(5)The population structure of T.chinensis in three site conditions were all clumped.But the cluster degree of it in Gebi desert and saline land were higher than that in sandy land.And there were significant difference among them(p<0.05).In the sandy land,the cluster degree of T.chinensis population of G3 coverage was much higher than that in the the G1 and G2 coverage.(6)The population structure of T.chinensis in sandy land was affected by the content of nitrogen,magnesium,organic matter,and moisture of soil.But by the soil organic matter and soil water content in saline land,and the soil nitrogen content,organic matter content and soil water content in Gebi desert.(7)The biomass models were established on the independent variables of ground diameter-height(D2H)and crown-height(CH).The equation between biomass and ground diameter-height(D2H)was y=AeBx,while the equation between biomass and crown-height(CH)was y=AeBx.The equation of crown-height(CH)had higher related with biomass.(8)Biomass of T.chinensis in sandy land,saline land,and Gebi desert was 11002.342okg/hm2,7548.739 kg/hm2 and 2235.037 kg/hm2 respectively.The ratio of carbon storage was Csandy land:Csaline land:CGebi desert=9.92:4.62:1.The order of carbon storage in different organ in sandy land was root > branch > stem,while stem > branch > root in the saline land and Gebi land.Carbon storage of aboveground was 1.21 times and 3.53 times higher than that of the underground in sandy land and saline land,respectively.(9)The value of carbon sequestration of T.chinensis forest was 39192.63 yuan/hm2 in the middle of Tarim River Basin,among which shurbs accounted for 80.79% and soil accounted for 19.21 %.