Construction of a health assessment system for Ficus microcarpa based on physiological indicators

Urban trees possess not only significant landscape and ecological value but also considerable cultural and medicinal importance. Establishing a rational tree health assessment system is crucial for evaluating tree health conditions and enhancing the management of urban garden trees. In this study, Ficus microcarpa was used as an example, and changes in 27 physiological indicators were measured under different health conditions through indoor pot experiments. Subsequently, 23 selected indicators were verified via outdoor sampling of old and ancient trees. Correlation analysis and principal component analysis were carried out, and seven key indicators were ultimately identified, namely, leaf moisture content, soluble sugars, flavonoids, malondialdehyde, gibberellin, peroxidase, and catalase. We obtained the individual health assessment model for F. microcarpa by calculating the adjusted comprehensive health score F based on the weighted contributions of three principal components. The constructed health assessment system categorizes tree health into four levels—healthy, sub-healthy, weak, and declining, which has been demonstrated to be objective, accurate, and feasible. The established tree evaluation system enables efficient, batch-scale health assessment of F. microcarpa, providing quantitative scientific support for urban tree management and conservation. Furthermore, the methodological framework described here offers a transferable template for developing physiology-based health assessment systems for Ficus trees and other tree species, including ancient and notable trees.