Serious disconnection among researches on individual physiological adaption, population genetic diversity and spatiotemporal demography has obstructed us in the knowledge of plant population ecology. Here we develop an approach to integrate those three research aspects by taking advantage of recent knowledge about DNA methylation and multivariate analysis. We show that by using various epigenetic parameters corresponding to individual physiological metabolic reprogramming potential, gene expression repression degree and physiological reaction characteristics, the contribution of various biotic and abiotic factors to an individual state and population structure can be quantified. Furthermore, population dynamics can be narrowly estimated by analysing DNA methylation of populations at different developmental stages. This study demonstrates an approach for the overall analysis of plant populations and exploring the spatiotemporal dynamics and developmental mechanisms of a population using Castanopsis chinensis as the model species.