Foliar Dynamics and Nutrient Retranslocation in an Age Series Plantation of Tectona grandis Raised in Moist Deciduous Forest Region, Northern India

Foliar dynamics strongly influences the nutrient pool in general and retranslocation enables plants to conserve and reuse nutrients in particular. Therefore, to have the understanding of such functions, patterns of monthly leaf mass changes and leaf area expansion, and annual nutrient retranslocation were studied in 1, 5, 11, 18, 24 and 30 years old teak plantations of moist deciduous forest region at the base of the Himalayas (29°3'-29°12' N and 79°20'-79°23' E). In these stands leaves kept on expanding and gaining mass from April to September. Leaf area and leaf mass varied between 376-473 cm² leaf^-1 and 3.3-5.0 g leaf^-1, respectively. Leaf area index (LAI) ranged from 1.49 to 7.6. Concentration of nitrogen (N) and phosphorus (P) was highest in summer while it was lowest in winter. Nevertheless, nutrient content of leaves was minimum in summer and maximum in rainy season or autumn. Average percent retranslocation values were 45.6 % (N), and 27.51 % (P) and average annual retranslocation were 29.957 kg ha^-1 yr^-1, and 2.186 kg ha^-1 yr^-1, respectively. Non-canopy stand (1 year) showed minimum retranslocation of both N and P. Although the retranslocation of N and P and leaf mass loss (LML) was prominent in all the stands regression relationship of N and P retranslocation with certain parameters like, LML, LAI, leaf area, leaf weight, stand age and basal area were not found significant (>5%). Nevertheless, the retranslocation data suggested that teak growing in tropical moist region is moderately efficient in nutrient conserving mechanism.