In Malaysian forests, the population dynamics of rattan has not been fully documented. Hence, this study was aimed to investigate the population dynamics pattern of the Calamus castaneus, a non-climbing rattan. The association of growth and phenology cycle to environmental variables on the population dynamics were studied for one year. Three forest reserves were selected as the study sites: Segari Melintang Forest Reserve (SMFR) in Perak, Teluk Bahang Forest Reserve (TBFR), and Bukit Mertajam Forest Eco-Park (BMFEP) in Penang. The fieldwork was conducted from March 2017 until March 2018. With the plot size of 10 m × 10 m (100 m²), five plots were established in each study site. All the C. castaneus individuals inside the plots were marked with numbered plastic tags. A total of 180 individuals were evaluated: TBFR (52 individuals), SMFR (86 individuals), and BMFEP (42 individuals). The findings have revealed that the C. castaneus abundancy is comparatively similar in all sites, as shown by the Kruskal-Wallis test with no significant difference (p > 0.05) between all life stages. The canonical correspondence analysis (CCA) for all sites has displayed that the rattan growth parameters are closely associated with the microclimate parameters and soil properties. Overall, SMFR showed the fastest growth increment and the largest population size of C. castaneus among all three sites.