Early growth and physiological characteristics of planted seedlings in La Mesa Dam Watershed, Philippines

Six-month-old native species of Erythrina variegata L., Dracontomelon dao (Blanco) Merrille et Rolfe, Pterocarpus indicus Willd. and Bischofia javanica Blume were planted to determine their growth and physiological characteristics. The study compared early growth performance among species and determined the suitable species in the area, compared growth performance of species in the flat and mountain areas, and determined the relationship between growth and physiological characteristics. A randomized block design of two blocks and three replicates per species was established at a spacing of 4 x 4 m between seedlings. Growth parameters used were height, root collar diameter, survival rate, fresh and dry weights, root-shoot ratio, root and shoot growth characteristics, leaf area and leaf anatomical characteristics. Physiological characteristics such as net photosynthesis, transpiration rate, water use efficiency, stomatal conductance, stomata size and number and chlorophyll content were determined and compared as well. Results and analysis revealed that among the four species, E. variegata showed best growth performance as it grew fast and fixed nitrogen. Based on the results, E. variegata has a potential in the reforestation of many denuded areas in the country since it grows fast and is shade-intolerant. In terms of physiological characteristics, nitrogen-fixing trees, E. variegata and P. indicus, exhibited good performance. Generally, the growth and physiological characteristics of four species in the mountain area which has fertile and moist soil conditions were better than in the flat area with its dry soil condition.