Vegetation analysis of the habitat of Strongylodon spp. in Bataan Natural Park and Subic Watershed and Forest Reserve

Vegetation analysis was done in three different sites within Bataan Natural Park and Subic Watershed Forest Reserve where Strongylodon spp. can be found. This was done using the belt transect method of sampling. A total of 291 trees, 106 lianas, and four epiphytes were encountered in a total combined area of 7, 200 m2. There were 76 species in 50 genera and 29 families of trees, 27 species in 24 genera belonging to 17 families of lianas, and 3 species in 3 genera and 3 families of epiphytes present in the sampling sites. Of these, 22 or 21% were endemic to the Philippines. Five species are classified as vulnerable in the IUCN Red List (2004) and two are classified as critically endangered. These species face threats due to limited occupancy or diminished quality of habitat, as well as actual or potential levels of exploitation. The total combined basal area of the 101 trees found in site 1, located at Sitio Minanga, Bgy Mabayo, Morong, Bataan, is 870.23 m2. Ficus nota is the species with the highest importance value index due to its high density value. Average height of the trees is 11.06 m and trees in the area were relatively of low stature. The total combined basal area of the 110 trees found in site 2, located at Sitio Kanawan, Bgy Binaritan, Morong, Bataan, is 1,041.39 m2. Mangifera sp. is the species with the highest importance value due to its high frequency value. Average height of the trees is 9.3 m and the trees were of low stature. The combined basal area of the 80 trees in site 3, located at Sitio Tarangkahan, Bgy Binaritan, Morong, Bataan, is 1,267.63 m2. F. nota is the species with the highest importance value index due to its high frequency and density values. All three sites are classified as secondary lowland dipetrocarp forests. Site 2 exhibited the highest diversity based on the Shannon-Wiener index. Strongylodon spp. found in the three sites is associated with at least 106 possible plant species. It has a high water requirement, favors the shaded area of the canopy, thrives in areas with high relative humidity, and grows on acidic loam to sandy loam soils. The density is 2 to 3 individuals in an area of 2,400 m2.It is a threatened species due to over collection and habitat destruction