Estimation Of Shrub And Grassland Vegetation Aboveground Biomass Using Photography Method

Shrub and grassland vegetation ecosystems are the most widely distributed in terrestrial ecosystems,they play an important role in the ecosystem of arid and semi-arid region,and the biomass estimated method of shrub and grassland vegetation with high-precision and non-destructive becomes an urgent need.Biomass of the ecosystem as the basic data characteristics,reflecting the material production capacity of ecosystem.What'is more,it'is a foundation to studying the material cycle,energy flow and productivity of terrestrial ecosystems.Therefore,depth study of shrub and grassland vegetation aboveground biomass have great significance in the development of animal husbandry,maintenance of biological diversity,preservation of soil and water,maintaining the ecological balance as well as regulating climate in the global carbon cycle.In this paper,the digital photograph method exploratory studies the feasibility of eight species shrub including Sophora davidii,Prunus davidiana, Hippophae rnamnoides,Caragana purdomii,Syringa vulgaris,Ostryopsis davidiana, Vitex negundo var.heterophylla,Poliothyrsis sinensis and grassland vegetation aboveground biomass estimation use of digital photos.Depth analysis of correlation between the variables extracted from digital photographs and biomass,as well as accuracy of the shrub and grassland vegetation aboveground biomass estimation model. Such non-destructive,simple and convenient,with high-precision digital photograph method provides a theoretical basis for widely used in the shrub and grassland vegetation aboveground biomass estimation.The results show that:Shrub photos image directly reflect the growth of shrub.Generally,plants that grow well are bound to have a larger area.The analysis showed that the strong correlation between area of shrub(S) and biomass.So that,the area of shrub is a very important variable in biomass estimation model and can be used to estimate its biomass.Use of the most relevant variables as independent variable to set up the best biomass estimation model of shrub.The regression equations were significant and have a very good estimation accuracy,with the coefficient of determination have 0.930 exception of Ostryopsis davidiana at 0.818.The area of shrub as independent variable and biomass as dependent variable to set up linear function,power function and cubic polynomial estimation model that have a good fitting effect,exception of Ostryopsis davidiana has low coefficient of determination some others at above 0.90,the results are very satisfactory.At the same time,use of the area of all shrub creation of one general linear model to break the boundary of shrub species.The determination coefficient(R~2) of general model reached more than 0.927.The regression equation has highly significant and precision to estimate the biomass.There is a significant correlation between grassland vegetation coverage extracted from digital photographs and biomass,and the correlation coefficient reachs more than 0.931.So that,the digital photograph can be used to estimate the shrub and grassland vegetation aboveground biomass,and provides a more accurate,convenient method for the field estimation biomass.