Distribution, Diversity and Spatial Analysis of Tree Species in a Long-Term Ecological Research Plot in Molawin-Dampalit Watershed, Mount Makiling Forest Reserve

A two-hectare long-term ecological plot (LTERP) was established to generate data for biodiversity resource assessment, monitoring and evaluation of Mo- lawin-Dampalit watershed for adaptive management. The plot was subdivided into fifty 20mx20 subplots where species identification, diameter at breast height (DBH) and total tree height measurements and geographic location of all trees were conducted. Growth parameters such as DBH and height were used to mon- itor and evaluate the area. The study recorded a total of 1,266 tree individuals comprising with 135 species distributed among 95 genera and 58 families. Of the 135 species recorded, 87 species are native or indigenous and 4 species are exotic or introduced in the area and 44 species are endemic to the Philippines giving an overall endemism profile of 32% for the whole study area. Three most dominant species include Diplodiscus paniculatus Turcz, Celtis luzonica Warb. and Pinanga insignis Becc based on Species Importance Value. A total of 29 threatened species were recorded in the area. The study revealed dominance of threatened species in the LTERP area. Out of 10 dominant species, 7 are threat- ened species and 3 of which are critically endangered species such as Parashorea malaanonan (Blanco) Merr and Diospyros blancoi A. DC. Tree diversity analysis showed a high species richness (135), evenness (0.71), Simpson diversity index (0.91) and Shannon Diversity Index (3.52) indicating a more diverse area, pre- served and intact MMFR. Spatial analysis was correlated with the clustering of species using ordination method. Results showed species composition is affected by spatial distribution and each subplot may have different site requirements and unique floral characteristics. K e ywords : Biodiversity resource assessment, dominant species, critically endan- gered species, abundant and tree diversity