Spectral phenology features of Platycladus orientalis (L.) Franco

Botanical Garden, Academy of Biology and Biotechnologies, Southern Federal University, Rostovon-Don 344006, Russia

^* Corresponding author: pdmitriev@sfedu.ru

Abstract

Spectral plant phenology, based on time series of vegetation indices, is a useful tool for monitoring vegetation condition and climatic changes. The chlorophyll/carotenoid index (CCI) and photochemical reflectance index (PRI) show promise for spectral phenology of coniferous plants. This study evaluates the potential of using CCI, PRI, and the normalised difference vegetation index (NDVI) as phenological metrics for Platycladus orientalis. The study found a strong correlation between the annual dynamics of the chlorophyll/carotenoid ratio (Chl/Car) and the time series of CCI (R² = 0.89, p < 0.001) and PRI (R² = 0.85, p < 0.001). The CCI time series was used to determine the beginning and end of the phenological vegetation period (PVP) of P. orientalis through a double logistic regression model. The PRI model had an error of approximately two weeks in predicting the beginning and end of the PVP, with a tendency to overestimate the duration of the PVP. The use of NDVI as a model is unsuitable for describing the P. orientalis 2023 PVP.