Study Of Biomass And Its Models Of Main Shrub Community Type In Northwest Sichuan

Biomass is significant in the research of global carbon cycle and climate change. As shrubs is an important ecosystem types (forest types accounted for 10% 30%),biomass research in it has a great value in the accurate estimation of carbon storage and flux in terrestrial ecosystems. 21.4% shrub of China distribute in Sichuan Province widely, while the north-west are mainly distributed region of Sichuan. As yet, far less information is available on the system to the northwest of Sichuan shrub biomass. Therefore, the study model a regression system of Coriaria nepalensis Wall, Rosa omeiensis Rolfe, Berberis julianae Schneid and Zanthoxylum tibetanum Huang mathematically and discuss the four shrubs biomass and distribution and spatial distribution of roots preliminaryly in northwest Sichuan for the first time.(1) We modeled regression systems of Coriaria nepalensis Wall, Rosa omeiensis Rolfe, Berberis julianae Schneid and Zanthoxylum tibetanum Huang using a linear regression model, polynomial model, power function model, exponential model and logarithm model in northwest Sichuan for the first time, conclusions as the following:â‘ The model with the parameter of D²H used to estimate the four shrub biomass can be achieved very good results fitting.â‘¡The fittest model for the biomass of organs,the ground and underground part and the total were polynomial model,power function model and linear model,while the polynomial was the best one.(2)We analyzed biomass and distribution of Coriaria nepalensis Wall, Rosa omeiensis Rolfe, Berberis julianae Schneid and Zanthoxylum tibetanum Huang systematic in the northwest Sichuan for the first time, the study shows that:â‘ The community biomass per hm² varied among plantation community types following the order: Coriaria nepalensis Wall(17 455.220kg/hm²)>Berberis julianae Schneid(12 208.421kg/hm²)>Zanthoxylum tibetanum Huang(11 000.713kg/hm²)> Rosa omeiensis Rolfe(10 091.298kg/hm²).Coriaria nepalensis Wall biomass being higher than the other three shrubs is mainly due to Coriaria nepalensis Wall nodule having a higher N₂-fixing capacity to promote the growth of the surrounding plants. Biomass of each component and the proportion of components to the total is different respectively for these four shrub community.â‘¡In the four shrub, Coriaria nepalensis Wall population biomass is much larger than the other three shrubs, up to 3 796.879kg/hm², and Rosa omeiensis Rolfe, Berberis julianae Schneid and Zanthoxylum tibetanum Huang populations biomass were 587.337kg/hm², 430.691 kg/hm², 734.002kg/hm². Biomass of each component and the proportion of components to the total differed, Coriaria nepalensis Wall biomass in different organs was in the order of root> stem> leaf> branch> bark; Rosa omeiensis Rolfe biomass in different organs was in the order of root> stem> branch>bark> leaf ; Berberis julianae Schneid biomass in different organs was in the order of stem> root> leaf> branch>bark> fruit; Zanthoxylum tibetanum Huang biomass in different organs was in the order of stem> root> branch> leaf> bark> fruit. Biomass distribution of four shrubs shows that the biomass distribution of each component has an important relation with its biological characteristics and environment.â‘¢The total root biomass per hm² varied among plantation population types following the order: Coriaria nepalensis Wall(1 175.028kg/hm²)>Rasa omeiensis Rolfe (238.290kg/hm²)>Zanthoxylum tibetanum Huang(158.413kg/hm²)>Berberis julianae Schneid(100.407kg/hm² ).The biomass fractiongs of a given root size class compared to the total root biomass differed among plantation population types.(3)For all four studied plantation types,the majority of the roots were distributed in the top 20cm of soil, e.g.76.71% for Coriaria nepalensis Wall population, 93.44% for Rosa omeiensis Rolfe, 91.11% for Berberis julianae Schneid, and 95.66% for Zanthoxylum tibetanum Huang population. Four shrub root biomass distribution characteristics of this region and northwest Sichuan is closely linked to climate and soil. The root allocation in the 0～20,20～40,and 40～60cm soil layers gave ratios of 11:2:1 for Coriaria nepalensis Wall,463:32:1 for Rosa omeiensis Rolfe, 178:16:1 for Berberis julianae Schneid, 178:7:1 for Zanthoxylum tibetanum Huang population. This is due to in different holt plant growth with different characteristics, making the shrub land in different soil layers within the root biomass of There is a certain difference.