Objective This study aimed to analyze the relationship between the stand structure and ecological service functions of early-stage Eucalyptus plantations, clarify the impact of stand structure on ecological service functions, and provide a theoretical basis for improving the quality and efficiency of Eucalyptus plantations.

Method In Luoding City of Guangdong Province, 12 plots of 20 m×20 m were established to conduct surveys and analyses on stand structure and ecological service functions. Descriptive statistics and Pearson correlation analysis methods were used to analyze the relationship between nine stand structure indicators (DBH kurtosis, DBH skewness, DBH Gini coefficient, tree height kurtosis, tree height skewness, tree height Gini coefficient, angular scale, size ratio, and aggregation index) and five ecological service functions (carbon sequestration and oxygen release, water conservation, air and environment improvement, soil conservation, and biodiversity protection), and to explore the association mechanism between stand structure and ecological functions.

Result The DBH and tree height structures of early-stage Eucalyptus plantations were approximately normally distributed. The angular scale, size ratio, and aggregation index of the plantations showed that the overall distribution of the plantations was relatively uniform, with local aggregation. The values of ecological service functions of the plantations from largest to smallest were as follows: Carbon sequestration and oxygen release > water conservation > biodiversity protection > soil conservation > air and environment improvement. The tree height kurtosis and skewness of the plantations were significantly positively correlated with the carbon sequestration and oxygen release function of the plantations. The DBH Gini coefficient of the plantations was significantly positively correlated with the temperature regulation function of the plantations. The angular scale of the plantations was significantly negatively correlated with the oxygen release function of the plantations.

Conclusion Increasing the uniformity of tree distribution in the horizontal structure and enhancing the heterogeneity of tree height distribution in the vertical structure of the plantations are conducive to promoting the ecological service functions of the plantations.