Abstract :
This study was conducted at the Visayas State University Arboretum in Baybay City, Leyte, and a reforestation site in Ormoc City. It aimed to compare the N and P Resorption Efficiency (%) of four dipterocarp species; namely, Hagakhak (Dipterocarpus validus), White Lauan (Shorea contorta), Bagtikan (Parashorea malaanonan), and Yakal-Saplungan (Hopea plagata); and determine which nutrient is limiting based on such parameters. The mature leaves of Hagakhak had the highest N content while Yakal-Saplungan had the lowest. In the senesced leaves, all the four species had comparable amounts of N. Phosphorus contents in the mature leaves of all the four species were significantly highest in White Lauan, while Bagtikan, Hagakhak, and Yakal-Saplungan contained similar amounts. In the senesced leaves, Hagakhak and White Lauan had comparable P content which was higher than those in Bagtikan and Yakal-Saplungan. The four dipterocarp species had a Nitrogen Resorption Efficiency (NRE) of 32.2%-54.6% with a mean of 41.09%. Phosphorus Resorption Efficiency (PRE) ranged from 36.2% - 62.1%, with a mean of 50.7%, which were higher than the NRE values. This means that Yakal-Saplungan and Bagtikan are more efficient in recycling P in the leaves than Hagakhak and White Lauan, making them better adapted to P-deficient soils. The consistently high PRE compared to NRE suggests that P is more limiting than N in the soils of both sites.