ROLE OF LIGHT, MOISTURE AND NUTRIENT AVAILABILITY IN REPLACEMENT OF QUERCUS LEUCOTRICHOPHORA BY PINUS ROXBURGHII IN CENTRAL HIMALAYA

Abstract

In large areas of Central Himalaya, Quercus leucotrichophora forests are being replaced by Pinus roxburghii. To determine the role of light, moisture and nutrient availability in this replacement, seedlings of these two species were planted separately and in mixture and the performance of each in the presence of the other was examined. It was found that in all conditions, P. roxburghii had more dry mass yield over Q. leucotrichophora and this became more pronounced in higher resource availability. Competition effect and relative crowding coefficient also indicated that P. roxburghii is superior in obtaining resource. This competitive superiority of P. roxburghii also increased with increasing resource availability. Relative yield total also showed some niche differentiation between these two species. Continual man-made disturbances, which allow more light and nutrient availability, have enabled P. roxburghii to invade Q. leucotrichophora forest and to establish stable stands.