Factors Constraining the Natural Regeneration of Alibangbang (Bauhinia malabarica Roxb.) in Carranglan Watershed, Nueva Ecija, Philippines

Abstract

Field experiments on insect infestation, rodent predation and seed viability were conducted to determine the causes of natural regeneration failure of Bauhinia malabarica Roxb. in Carranglan Watershed. The larva of Caryedon serratus (Olivier) infested the pods and seeds of Bauhinia malabarica with a mean infestation rate of 78.32 % and 73.23 %, respectively. Other experimental trees recorded a mean infestation rate of 75.00 % on pods and 71.19 % on seeds. Examination conducted in different parts of the watershed obtained a mean infestation rate of 65.00 % and 67.80 % on pods and seeds, respectively. On the other hand, rodents were not eating ripened seeds of the species since no predation was observed. On viability test, only 47.50 % germination was obtained in seeds soaked in tap water for 24 hours. This treatment had the earliest germination period (7.75 days), longest total germination period (52 days) and highest germination value (3.32). Similarly, it recorded the highest root length (5.73 cm), total length (12.34 cm) and seedling vigor index (585.62).On the other hand, seeds alternately soaked in tap water and hot for 30 seconds had the highest germination energy (40.75 %). Therefore, serious infestation on Bauhinia malabarica seeds and low viability limits the regeneration of the species in the watershed.