Analysis Of Carbon Concentration And Allometric Growth Model Of Biomass And Carbon Content For Larix Olgensis

Forest carbon storage accounts for about 45%of terrestrial carbon storage,and improving the estimation accuracy of forest carbon storage is conducive to improving the scientific management and planning level of forests.Larix Olgensis is an important economic conifer species in Northeast China.In this study,the artificial Larix Olgensis in the northeast forest area was taken as the research object.Based on the data of 77 sampling trees of Larix olgensis from Mengjiagang,Shangzhi Maoershan,Xiaojiu Forest Farm and Dongjing,Linkou Forestry Bureaus of Jiamusi City,Heilongjiang Province from 2015 to 2018.Analyze the variation of carbon concentration in each component(ie,wood,bark,branch,foliage and root)of Larix olgensis,and based on the measured data of biomass and carbon content,the mono-element and dual-element additive models of carbon content for each component of Larix olgensis were developed,while nonlinear seemly unrelated regression was used to estimate the parameters in the additive models,and the jackknife resampling technique was used to verify and evaluate the developed models.At the same time,the direct method and indirect method were compared to estimate the difference in accuracy of carbon content in each component and the distribution pattern of biomass and carbon content and the variation law of root-to-shoot ratio.Research indicates:(1)Diameter at breast height had a significant effect on the carbon concentration of wood and bark of Larix olgensis,and the interaction of each component and component with relative height had a significant effect on the carbon concentration of wood and bark.The size of the root and the position of branch and foliage within the canopy had no significant effect on carbon concentration.The results showed that the weighted mean carbon concentration of each component differed significantly,branches(49.3%)>bark(48.7%)>foliage(48.5%)>wood(48.2%)>roots(47.1%).(2)The adjusted coefficient of determination(Ra~2)of additive models of carbon content was greater than 0.89,the mean absolute error was less than 8.3 kg,and the mean absolute error percentage for most models was less than 30%.The adjusted coefficient of determination(Ra~2)of additive models of carbon content was greater than 0.89,the mean absolute error was less than 4.1 kg,and the mean absolute error percentage for most models was less than 30%.Adding tree height in the additive models of biomass and carbon content could significantly improve model fitting performance and predicting precision.(3)The results of variance analysis showed that there were significant differences among the five methods for estimating carbon content in single wood.The carbon allometric method is the best method for estimating the carbon content of a single tree,while the use of the general carbon content rate coefficient produces a significant deviation in estimating the carbon content of a single tree.(4)Aboveground biomass or carbon content accounts for about 80%of the total tree biomass or carbon content,while below-ground biomass or carbon content accounts for about20%.There is an obvious linear relationship between the aboveground biomass(or carbon content)and the belowground biomass(or carbon content)of Larix olgensis,the slope coefficients are about 0.26 and 0.25,respectively,and the R~2 is 0.91 and 0.91.The results of this study will improve the estimation accuracy of the biomass and carbon content of Larix olgensis in Northeast China,and promote the development of forestry carbon sinks.