Survival and Growth of Seedlings of Two Rhododendron Tree Species along an Altitudinal Gradient in a Temperate Broad Leaved Forest of Arunachal Pradesh, India

Sanjeeb Bharali,Mahamed Latif Khan,Lal Bihari Singha,Ashish Paul

doi:10.5923/j.plant.20120201.06

Abstract

Seedling survival and growth of two Rhododendron species viz., Rhododendron kenderickii and Rhododen- dron grandewere studied along an altitudinal gradient in a temperate forest. Differences in survivality and relative growth responses of the two selected rhododendrons in terms of height, collar diameter and leaf number were monitored seasonally. High seedling mortality was recorded highest in winter season as well as in the higher altitude. Both the species attain maximum growth in terms of height, collar diameter and mean leaf number during rainy season while, minimum in winter season. Moreover, both the Rhododendron species exhibit variation in growth response with altitude and higher total growth was recorded in lower altitude. The result of the present study showed that the survival and growth of seedlings of both the selected Rhododendron species were greatly influenced by altitude as well as season. This variability may be due to the variation in light, temperature, moisture and edaphic factors in various seasons as well as at different altitudes, which results into development of an array of microclimatic conditions for differential growth behavior of different species.

Highlights

Forest community structure and composition may be largely determined at early life history stages
High seedling mortality of both the selected Rhododendron species was recorded during the period of November to March, which experienced the cold and dry season (Figure 1)
Seedlings survival of Rhododendron kenderickiiwas recorded better both in Shagong as well as in Hanuman Camp while, R. grandeshows similar trend of survivorship in all the study stands which might be due to availability of uniform favourable conditions during growing season

Summary

Introduction

Forest community structure and composition may be largely determined at early life history stages. The most reliable indicator of successful restoration of forest communities is likely to be the number and composition of the woody seedlings colonizing naturally[1]. Plant populations usually go through major thinning during the seedling phase and the traits that affect seedling survival vary according to environmental conditions[3,4]. Survival and growth of tree seedlings are determined by the interactive influence of biotic and abiotic factors of the forest environment[5]. Because species vary greatly in their sensitivities to mortality agents at early life history stages, spatially variable environments greatly affect community composition of seedlings[11,12,13,14]. Tree seedling dynamics is affected by various environmental factors[15,16]

Methods

Results

Discussion

Conclusion