Given the interest in evaluating country-scale changes in biomass carbon stocks in the seasonal tropics using remote-sensing techniques, leaf phenology is a key parameter for regulating errors caused by uneven data collection and the degree of deciduousness in the imagery analyzed. We studied leaf phenology in two dry dipterocarp forests with different dominant species in Kratie and Kampong Thom provinces, Cambodia. One was a typical Indochinese forest dominated by Shorea siamensis , Shorea obtusa , and Dipterocarpus tuberculatus growing on shallow, relatively nutrient-rich soil (e.g., Plinthosol). No stand-level leafless areas were observed because of temporal variation in leaf shedding/flushing among individuals within the same species or among species. Due to habitat segregation of the dominant species, the leaf phenology showed topographical patterns. The other was a species-poor forest dominated by Dipterocarpus obtusifolius on deep, sandy, nutrient-poor soil (e.g., Acrisol). Although D. obtusifolius is generally regarded as a deciduous tree, neither the individuals studied nor other forest components were ever leafless. Thus, imagery analysis should account for various deciduous patterns.