With the aim of restoring the disturbed sites on one of the premier tiger reserve of the country or the only biosphere reserve of the state, the study was planned to investigate the effect of disturbance on seed germination, early seedling growth and adaptation potential of Cassia fistula (L.), Albizia lebbeck (L.) and Dalbergia sissoo Roxb. in Similipal Biosphere Reserve (SBR), Odisha. The study sites of the biosphere reserve was categorised into disturbed, moderately disturbed and undisturbed stands on the basis of disturbance index. They differ from each other in forest floor light intensities along with other biophysical characters. High light intensity in the forest floor of Disturbed Stand (DS) than Undisturbed Stand (UDS) and Moderately Disturbed Stand (MDS) of the reserve was found suitable towards significantly higher rate of seed germination and seedling growth of the three investigated tree (over storey) species for all growth characteristics measured except S/R ratio. High soil nutrient content and low light intensity in the forest floor of undisturbed stand than disturbed and moderately disturbed stands of the reserve was not suitable for better seed germination and early stage of seedling growth. Moderate light intensity in the forest floor of moderately disturbed stand produced seed germination and seedling growth to come in the second order. All growth characteristic parameters of Albizia lebbeck seedlings had almost the highest values among species in all the forest stands of the reserve. Though Cassia fistula seedlings had lower growth characteristics than others, but its low S/R ratio in all the forest stands evidenced its higher adaptation potential.