Carbon storage of poplar forests and soil in the lower reaches of the Tarim River and influencing factors

Forests play a significant role as carbon sinks and are crucial for achieving China’s dual carbon goals. This study focuses on Populus euphratica forests in the lower reaches of the Tarim River, specifically analyzing the spatial distribution of carbon storage in P. euphratica and soil, as well as the influencing factors, based on biomass allometric growth models. The results show that: (1) carbon storage in individual P. euphratica trees in the study area ranges from 1.71 to 502.32 kg·hm-2, with aboveground and belowground carbon storage ranging from 1.16 to 448.61 kg·hm-2 and from 0.55 to 53.71 kg·hm-2, respectively. Carbon storage in P. euphratica is mainly influenced by soil water content, total nitrogen, organic carbon, distance from the river channel, and tree age. As distance from the river channel increases, the root-to-shoot ratio decreases, whereas carbon storage both aboveground and belowground increases. Moreover, carbon storage aboveground is positively correlated with that belowground (R2=0.99). Carbon storage in individual trees increases with increasing distance from the river channel and tree age. (2) Soil carbon storage exhibits significant spatial heterogeneity (PP. euphratica and soil, with soil water content and total nitrogen showing the strongest correlation with carbon storage in P. euphratica. This study elucidates the distribution patterns of carbon storage in P. euphratica forests as well as the influencing factors, providing important insights for research on carbon cycling in regional riparian forest ecosystems.