Estimation and analysis of understory shrub biomass in Changbai Mountains

With 10 common species of understory shrub in three natural forest types,including Spruce-Fir Mixed forests,Polar-Birch secondary forests and Larch plantation in Jinggouling Plantation Changbai Mountains as test objects,crown area(Ac),project volume(Vc),square ground diameter by height(D2H) were used as variables in component biomass models.According to the growth forms,tree-like(single trunked) mixed models and shrub-like(multi-stemmed or low branching) mixed models were built.The shrub biomass along with its distribution in different species and components were investigated using the best-fit models which were judged by high R2 and low SEE.The results showed that the best-fit species-specific component model forms were linear,quadratic or cubic equations,the variables in stem and branch models were D2H or Vc,and in leaf models were Ac or Vc,while in root models were D2H.The best-fit mixed model forms were power or cubic equation,the variables in these models were D2H while the branch of mixed model of shurb-like plants was Vc.The biomass of understory shrub in natural Spruce-Fir Mixed forests,Polar-Birch secondary forests and Larch plantation was 4 013.59,3 950.66 and 4 649.36 kg/hm2 respectively,and tree-like plants make more biomass contribution than shrub-like plants.