Leaf nutrient status as a predictor for Mahogany (Swietenia sp.) fruit productivity

Soil fertility is one of the limiting factors for tree productivity. Trees as seed sources that have grown in low-fertility soil would not have sufficient edaphic supports for its physiological- and morphological- development, including fruit production. As the ambient environmental conditions are manifested in tree physiology, leaf nutrition status can be used for diagnosing soil fertility. This study aimed to test the possibility of leaf nutrient status as a predictor for Mahogany seed source productivity. The study examined six locations of mahogany fruit productions in West Java from February until December 2018. Soil and leaves samples were collected from fruiting and un-fruiting Mahogany trees, which have similar levels of generative and vegetative phases. Sampling was conducted two months after the fruiting season. Results showed that the fruiting phenomenon was highly correlated with Nitrogen (N) concentration in leaves after the fruiting phase of the tree. The N-total concentration of mahogany leaves obtained from six stands in Bogor and Cianjur were ranged from 1.76% to 3.66%, with an average of 2.33%. Trees that have N concentration above the average indicated a propensity of unproductive (not fruiting) in that year.