Construction of individual tree biomass models for major tree species in the forest ecosystem of Nanling Mountains

Abstract

Forest ecosystems represent the largest terrestrial carbon reservoir globally. Accurate quantification of forest biomass is critical for ecosystem service assessment, carbon sink trading, and supporting China’s dual-carbon climate targets. However, the lack of individual tree biomass models for dominant species in the heterogeneous habitats of the Nanling Mountains has hindered regional carbon accounting and sustainable forest management. Here, we employed cluster analysis to classify major tree species into functional types with consistent allometric growth strategies, enabling unified group-level biomass models that improve the accuracy and efficiency of regional stand biomass estimation. Using stem analysis method, we quantified stem, branch, leaf, and root biomass for each sampled tree. The allometric parameters of 13 widely used models were estimated via ordinary least squares regression. The results showed that: (1) 68 major tree species could be classified into 10 functional types. Leaf shape, taxonomic family, maximum potential height, and wood density were identified as the key traits driving functional type differentiation. (2) Biomass models were developed at the group level rather than for individual species. All 13 allometric models exhibited good performance in predicting organ biomass for each group. (3) Model validation confirmed strong performance across all groups, with adjusted R² values exceeding 0.90, low root-mean-square errors, and negligible systematic bias. These findings confirm the applicability of the developed models for estimating organ biomass across different tree species in Nanling Mountains. These models provide a regional biomass reference for subtropical natural forests, supporting more accurate forest biomass estimation, carbon stock assessment, carbon accounting, and forest management, thereby contributing to China’s dual-carbon goal and the construction of regional ecological security barriers.

Keywords

Biomass model / Carbon storage / Fitness / Major tree species / Nanling Mountains / Natural forest / Stem analysis / Tree structural components

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Funding

National Key R&D Program of China(2024YFF1306600)

Huitong Forest Ecological Station funded by the State Forestry and Grassland Administration of China(2023132053)

RIGHTS & PERMISSIONS

Northeast Forestry University