Afforestation species and slope as key drivers of soil carbon sequestration in plantations of the tropical-subtropical transition zone: a case study from Xishuangbanna, Southwest China

Abstract

Tree plantations in the tropical-subtropical transition zone (TSTZ) represent crucial ecological regions where diverse biomes converge. Investigating the carbon sequestration potential and dynamic changes within these plantation ecosystems is of considerable ecological significance. However, the spatial distribution, driving factors, and underlying mechanisms of carbon sequestration in plantations in this region are poorly understood, thereby limiting accurate assessments of their carbon sequestration potential. This study examines four types of plantation forests located within the TSTZ on the Puwen forest farm of Xishuangbanna, China. Two slope gradients were established to quantify and compare the rate of carbon sequestration across these ecosystems. Using random forest modeling and structural equation modeling, the study identifies key environmental factors influencing the rate of carbon sequestration in the plantations. The results reveal substantial variation in DBH growth rates, biomass carbon sequestration, and soil organic carbon sequestration rates (R_SOC) among the four forest types. Critical factors affecting R_SOC include leaf nitrogen and phosphorus concentrations (LP), total soil nitrogen (STN), total soil phosphorus (STP), soil available phosphorus, and nitrogen concentration in ground surface litter. Among these, STN and STP exerted positive effects on R_SOC, while LP is exerted negative. Overall, the concentration of soil carbon, nitrogen and phosphorus, along with the nitrogen and phosphorus levels in leaves, under different species and topographic slopes, play decisive roles in regulating soil carbon sequestration rates in tropical and subtropical plantations. This research provides support for vegetation protection and restoration in ecologically sensitive areas and watersheds, contributing to the enhancement of regional forest carbon sequestration capacity.

The online version is available at https://link.springer.com/.

Corresponding editor: Tao Xu.

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Keywords

Afforestation / Impact factor / Slope / Soil organic carbon sequestration / Tree species / Tropical-subtropical transition zone

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