Impact of Altitude on Population Structure and Regeneration Status of Two Rhododendron Species in a Temperate Broad Leaved Forest of Arunachal Pradesh, India

An attempt had been made to study the impact of altitude on population structure and regeneration status of two Rhododendron species as well as its associated species in a temperate forest of Arunachal Pradesh. Population structure was worked out based on the density of seedlings, saplings and adults while, the regeneration status was determined from the population size of seedlings, saplings and adults. The mid altitude site (Hanuman Camp) has highest density (2692 individuals ha-1) comprising of seedlings, saplings and adults of all species followed by lower altitude (Shagong) site (2379 individuals ha-1) and lowest at (Yarlung) higher altitude site (2180 individuals ha-1). However, the relative proportion of seedlings of all woody species was recorded highest in low altitude site, while it was lowest in higher altitude. Conversely, the relative proportion of saplings and adults were highest in higher altitude. The selected Rhododendron species shows reverse J shaped population structure and fair regeneration status in all study stands having higher number of seedlings compared to saplings. However, the number of saplings is less than the adults. It was observed that the seedling populations dominate the overall population of the selected Rhododendron species. Moreover, it was found that although altitude does not affect regeneration status, but affects the population structure of the selected Rhododendrons. The fluctuation in population density of seedlings, saplings and adults along the altitudinal gradient may be linked with the prevailing environmental factors.