TAILIEUCHUNG - Báo cáo lâm nghiệp: "Estimation of the biomass stock of trees in Sweden: comparison of biomass equations and age-dependent biomass expansion factors"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài:"Estimation of the biomass stock of trees in Sweden: comparison of biomass equations and age-dependent biomass expansion factors" | Ann. For. Sci. 62 2005 845-851 INRA EDP Sciences 2005 DOI forest 2005075 845 Original article Estimation of the biomass stock of trees in Sweden comparison of biomass equations and age-dependent biomass expansion factors Anneli jALKANENa Raisa MAKIPAAb Goran STẢHLc Aleksi LEHTONENb Hans PETERSSONc a University of Helsinki PO Box 27 00014 University of Helsinki Finland b Finnish Forest Research Institute Unioninkatu 40 A 00170 Helsinki Finland c Swedish University of Agricultural Sciences Forest Resource Management and Geomatics 901 83 Umeâ Sweden Received 13 April 2004 accepted 14 March 2005 Abstract - Differences and uncertainties of alternative methods applicable to estimation of biomass in national greenhouse gas inventories are evaluated. The alternative methods employed to obtain biomass estimates of trees are 1 aggregated stand-level volume estimates multiplied by biomass expansion factors BEF and 2 biomass equations applied to tree-wise data of a national forest inventory. In comparison to the reference value obtained using tree-wise biomass equations the age-dependent BEFs for the whole of Sweden resulted in a lower aboveground biomass estimate. The estimates were the closest for conifer-dominated forests in central Sweden and the largest discrepancies were for spruce in southern Sweden. This result indicates that these age-dependent BEFs cannot be applied to conditions where stand development deviates from the conditions under which the BEFs were developed. The degree of uncertainty in both methods was highest in the young age-classes. At the regional level the relative standard errors of the BEF-based biomass estimates were in the range of 4-13 . biomass function carbon stock of trees forest inventory greenhouse gas inventory uncertainty Résumé - Estimation de la biomasse sur pied en Suède comparaison des equations de biomasses avec les facteurs d expansion de la biomasse BEF lies à l âge. Nous avons évalué les differences et les incertitudes

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