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Scientia Silvae Sinicae ›› 2025, Vol. 61 ›› Issue (1): 57-69.doi: 10.11707/j.1001-7488.LYKX20230562

• Research papers • Previous Articles     Next Articles

Scale-Compatible and Tree Species-Classified Forest Carbon Storage Model of Volume-Derived in China

Cong Zhang,Qi Liu,Haikui Li*(),Pengju Liu,Siying Zhan   

  1. Institute of Forest Resource Information Techniques, Chinese Academy of Forestry Key Laboratory of Forest Management and Growth Modelling, National Forestry and Grassland Administration Beijing 100091
  • Received:2023-11-22 Online:2025-01-25 Published:2025-02-09
  • Contact: Haikui Li E-mail:lihk@ifrit.ac.cn

Abstract:

Objective: A simple and convenient method for estimating forest carbon storage was proposed, and a scale-compatible and tree species-classified forest carbon storage model of volume-derived was constructed, which provided a method and technology support for estimating forest carbon storage of multi-scale and multi-tree species. Method: Based on the data of the 6th?9th national forest resource inventory and allometric growth equation, the scale-compatible and tree species-classified stand carbon storage model considering stand origin and age group was constructed by using the independent model of non-linear least square method and the simultaneous equations model of non-linear seemingly unrelated regressions with dummy variables. Heteroscedasticity was eliminated by weighted regression, and the model was evaluated by determination coefficient (R2), standard error of estimate (SEE), mean prediction error (MPE), total relative error (TRE) and variance percentage (VP). Meanwhile, using the data of the National forest and grass ecological comprehensive monitoring in 2021, the differences of forest carbon storage estimation by different scale models were compared. Result: 1) A total of 2 974 scale-compatible forest carbon storage models were constructed. Compared with the independent model, there was no significant difference in R2 of the simultaneous equations model. The independent model and the simultaneous equations model were 1 383 and 1 591 categories, respectively. The average values of the model R2 were 0.966 1 and 0.965 2, MPE were 0.75% and 0.78%, respectively, the R2 of the simultaneous equations model only decreased by 0.000 9, and the MPE only increased by 0.03%. 2) A total of 2 520 tree species-classified forest carbon storage models were constructed. As with the results of the scale-compatible model, there was no significant difference in R2 between the independent model and the simultaneous equations model. The independent model and the simultaneous equations model were both 1 260 categories. The average values of the model R2 were 0.944 3 and 0.942 4, MPE were 0.48% and 0.49%, respectively, the R2 of the simultaneous equations model only decreased by 0.001 9, and the MPE only increased by 0.01%. 3) Four forest carbon storage models with different modeling methods (independent-scale model, independent-tree species model, simultaneous-scale model, simultaneous-tree species model) were established. Compared with the independent model, the parameters variation of the simultaneous equations model was smaller. Four forest carbon storage models with different modeling methods contained 46 157 and 23 935 parameters a and b respectively. The average values of parameter a in the independent model and the simultaneous equations model were 0.596 5 and 0.620 0, respectively, and the ranges were 2.318 6 and 2.192 2, respectively. The range of parameters in the independent model was 0.126 4 higher. The average values of parameter b were 0.933 2 and 0.931 8, respectively, and the ranges were 0.672 3 and 0.505 6, respectively. The range of the independent model was 0.166 7 higher. 4) When estimating national forest carbon storage by different scale models, regardless of the scale, the estimation difference of the independent model was higher than the simultaneous model. However, in general, the estimation differences at various scales were within 3%. Conclusion: 1) The volume-derived forest carbon storage model proposed in this paper from stand volume to stand carbon storage was effective and reliable, which can be used to directly estimate forest carbon storage. 2) Based on the simultaneous equations model of non-linear seemingly unrelated regressions with dummy variables, the scale-compatible and tree species-classified forest carbon storage model can be better established. 3) The average R2 of the forest carbon storage model constructed in this paper was above 0.95, and MPE was less than 1%, which can be used to quickly and accurately estimate forest carbon storage in forestry practice. 4) According to the fitting accuracy of the model and the stability of the parameters, we recommend using the simultaneous-tree species model. 5) Under the accuracy requirement of 5%, the national scale model can be used to estimate the national forest carbon storage.

Key words: forest carbon storage model, nonlinear likelihood independent, dumb variable, parameter database, scale-compatible, tree species-classified

CLC Number: