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

Seedling survival and growth of two Rhododendron species viz., Rhododendron kenderickii and Rhododendron 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.