A study on the density, population structure and regeneration of Red Sanders Pterocarpus santalinus (Fabales: Fabaceae) in a protected natural habitat - Sri Lankamalleswara Wildlife Sanctuary, Andhra Pradesh, India

Abstract

Pterocarpus santalinus is a highly valued medium-sized leguminous endemic tree with a restricted range in the southern Eastern Ghats deciduous forests.  The enumeration in four 1ha plots has yielded a total of 878 Red Sanders tree individuals (≥30cm girth at breast height - gbh) with a range of 165–246 individuals per ha and 9–51 individuals per 0.01ha.  The size class structure revealed that the majority of individuals occurred in lower gbh classes with 364 individuals (39.5%) in 30–50 cm gbh class and 420 individuals (45.6%) in 51–70 cm gbh class, while in the higher gbh class (71–90 cm gbh) only 129 individuals (14%) and seven individuals in >90cm gbh class were recorded.  Overall the population structure indicated a low ratio change in lower gbh classes suggesting a stable population.  A higher percentage of life stages in recruitment stage like seedlings and saplings than trees was observed and the feature of re-sprouting from roots after fire damage was also recorded.  A bottleneck progress from regenerating trees to adult trees was noticed, may be due to slow growth of the species.  High stem density and presence of individuals in all the regenerating and reproductive classes suggest that Red Sanders is tolerant to mild disturbance.  But the drastic reduction in the density in higher gbh class reflects the concern for recruitment in future as it may affect the seed output due to loss of reproductively fit mature trees.