In its natural habitat, S. platyclados is abundant in Martelu Purba Nature Reserve, North Sumatra. However, like the Dipterocarpaceae family, this species has limitations in regeneration related to the uncertain flowering phase and the seeds' recalcitrant nature. This condition can be a long-term threat to the sustainability of S. platyclados. Efforts should be made to select mother plants as a source of short-term quality seeds, to support the breeding program and the conservation of S. platyclados. Monitoring of mother plants will be more effective if mapping data is available. Therefore, it is important to map the mother plant of S. platyclados. In addition, the population structure needs to be identified and related to trends in its sustainability. The goal of this study was to map the mother plant of S. platyclados in Martelu Purba Nature Reserve and to examine its population dynamics.. This research was conducted in Martelu Purba Nature Reserve, Simalungun Regency, North Sumatra. There are 195 hectares of designated population there. Combining the path method and the plotline, the sampling methodology was applied. Fifty (50) plots were observed across the sample area of 2 hectares (1% Sampling Intensity), which was separated into three lanes. Observations were made on a 20 m × 20 m plot to measure the vegetation at the tree level (diameter 20 cm), a 10 m × 10 m observation sub-plot to measure the vegetation at the pole level (diameter 10cm - 20m), a 5 m × 5 m observation sub-plot to measure the vegetation at the sapling level (diameter 10 cm), and a 2 m × 2 m observation sub-plot to measure the vegetation at the seedling level. The mother plants were recorded as many as 309 individuals in 50 observation plots, or 155 individuals/ha spread evenly in the relatively sloping Nature Reserve area. The distribution structure of the height and diameter of the mother plants indicates a good adaptation, resembles a standard curve. The population structure of S. platyclados is curved like an inverted J, indicates that this population is quite stable and sustainable. However, monitoring at the pole level is crucial based on a gap in the presence of this regeneration compared to others.