Shanshan Jin

Urban trees play a dual role in enhancing landscape aesthetics and contributing to carbon sequestration. This study evaluated the biomass and carbon storage of eight common urban tree species in Zhengzhou, China, using organ-specific measurements and allometric growth models. The results revealed that biomass and carbon were primarily allocated to the trunk, followed by the roots, branches, and leaves; these results are consistent with previous findings. Acer buergerianum Miq. and Magnolia grandiflora L. demonstrated the highest per-tree carbon storage, while Styphnolobium japonicum (L.) Schott and Salix babylonica L. performed better in carbon storage per unit area. These patterns are linked to variations in species morphology, growth performance, and planting density. The study provides evidence-based recommendations for optimizing urban tree species selection to enhance carbon sink capacity. Future applications include integrating these results into urban planning strategies and long-term carbon monitoring systems, thereby contributing to low-carbon city development.

An interspecific association represents an inter-relatedness of different species in spatial distribution and combined with the altitude factor, is key for revealing the formation and evolution of an ecological community. Therefore, we analyzed the changes in interspecific association and community stability at different altitudes in the southern Taihang Mountains using the variance ratio (VR), χ² test, association coefficient (AC), percentage of co-occurrence (PC) and Godron stability method. In total, 27 sample plots measuring 20 × 20 m were set up and were divided into lower altitude (700~1100 m), medium altitude (1100~1500 m) and higher altitude areas (1500~1900 m) into. The results showed that the overall interspecies association of communities exhibited an insignificant negative association in both the lower (VR = 0.79, W = 7.15) and higher (VR = 0.81, W = 7.36) altitude areas, while an insignificant positive association was observed in the medium (VR = 1.48, W = 13.34) altitude area. Besides, the χ² test showed the ratio of positively and negatively correlated species pairs decreased as altitude increased with values of 1.39, 1.22 and 0.95 in the lower, medium and higher altitude areas, respectively. Moreover, the AC and PC indices stated that most species pairs had a weaker association in the three altitude areas, but the AC indices also suggested the number of positive association species pairs was more than that of negative association only in medium altitude area. Meanwhile, the Godron stability method showed the distances from the intersection point to the stable point (20 and 80) were still far away, with values of 22.53, 11.92 and 21.34 in the lower, medium and higher altitude areas, respectively, which indicated an unstable succession stage, though the community appeared steadier in the medium altitude area. This study can provide some guidance for effective afforestation and vegetation restoration.