Structure, composition and diversity of trees and shrubs on northern and southern aspect in indigenous agroforestry systems of Thauldhar block in district Tehri of Uttarakhand

Three indigenous agroforestry systems viz. agri-siviculture (AS), agri-horti-silviculture (AHS) and agri-horticulture (AH) systems in Thauldhar block of district Tehri Garhwal of Uttarakhand state between 1000 to 2000 m asl elevation were studied. A sum of 19, 21 and 11 tree species was recorded on northern and 15, 13 and 09 on southern aspect under AS, AHS and AH systems. The shrub species observed 16, 16 and 13 on northern and 15, 13 and 11 on southern aspect under AS, AHS and AH systems. The highest tree density (8.30 trees/100m²) was recorded in AH system on the northern aspect and AS system (5.05 trees/100m²) on the southern. The utmost shrub density 17.60 shrubs/25m² in AS system and 11.55 shrubs/25m² in AHS system was recorded on northern and southern aspect respectively. On the basis of higher IVI values the Grewia optiva and Melia azedarach under AS system, Quercus leucotrichophora and Celtis australis under AHS system and Melia azedarach and Prunus domestica under AH system on the northern aspect recorded dominant and co-dominant species. The Melia azedarach, Grewia optiva under AS, Grewia optiva, Musa paradisiacal under AHS and Prunus armeniaca, Citrus sinensis under AH system on the southern aspect noticed dominant and co-dominant species. The Shannon index is almost higher on northern aspect and Simpson Index on the southern aspect in different agroforestry systems. The highest diversity, species richnessand and beta diversity were observed in AHS system and least in AH and AS system.