Microclimatic correlates of early regeneration of Lagerstroemia speciosa (L.) Pers under natural forest conditions in Mizoram, Northeast India

Understanding seedling dynamics is essential for evaluating natural regeneration and guiding restoration strategies. This study monitored seedling emergence, survival, and growth of Lagerstroemia speciosa under natural forest conditions in Mizoram, Northeast India, using 10 permanent sample plots (1 m × 1 m) monitored fortnightly over a three-year period (2023-2025). Key microclimatic variables, including soil moisture, soil temperature, relative humidity, rainfall, air temperature, soil pH, and litter thickness were recorded alongside seedling performance. Across the monitoring period, the findings revealed that mean seedling emergence ranged from 2.4 ± 2.01 to 5.6 ± 7.62 seedlings per plot, with an overall survival rate of 53.85%, with significantly higher mortality (35.90%) during the dry winter months. Seedling growth increments were positively correlated with soil moisture (seedling height: r = 0.60, P < 0.001 and stem diameter: r = 0.44, P < 0.001) and soil temperature (seedling height: r = 0.52, P < 0.001 and stem diameter: r = 0.45 P < 0.001), while negatively correlated with soil pH (seedling height: r = - 0.27, P < 0.001 and stem diameter: r = - 0.22, P < 0.01). These results demonstrate that moisture availability and seasonal microclimatic variability are primary drivers of early regeneration. From a management perspective, these observational findings suggest that protecting microsite with adequate soil moisture and healthy accumulation of organic plant matter may improve establishment outcomes, though further research is needed to confirm the impact of canopy structure on the regeneration dynamics of L. speciosa.