Author : Baguinon, Nestor T.

Summary : The study was conducted in Sitio Kayasan, Bgy. Tagabinit, City of Puerto Princesa, Palawan, from August 1, 1995 to February 20, 1996. A patch of virgin forest surrounds this limestome rock and the author established 32 square plots in a line plot layout, each with 20 x 20 sq.m. dimension. Two more plots were located 3 km northeast from Kayasan and another two 13 km away. The study discovered that 31 percent of the variations among 36 stands in terms of 15 soil variables may be explained by a function which is a linear combination of soil variables Clay, N, OM, Sand, CEC and pH while another 22 percent of the same may be explained by a second function which is a linear combination of mostly micronutrients namely Ca, Mn, Zn, Cu and Mg. Stepwise regression analysis extracted from the first function only Ca, Mn, Zn, and Cu. PCA and regression scores when independently plotted in two scattergrams showed similar results. Ordination by Principal Component Analysis (PCA) and Multidimensional Scaling (MDS) found that the line plot layout of 35 samples can be classified into the following groupings: young second growth forest (SGF), advanced SGF, outliner old growth forest (OGF) with some SGF characteristics, OGF with Magpanggamot (cf. Shorea sp.) and OGF without Magpanggamot. Using Stepwise Multiple Regression Analysis (SMRA), the study found that some of PCA scores correlated with some environmental variables measured, namely, CEC, Clay, N, OM, Sand, Silt, P, Ca, Cu, Mn, Zn, pH, Fe, Mg, Landpost (plot position on valley, midslope or ridge), Longtude (Longtitude, Altitude (meters above sea level) and Slope (percent gradient). The study estimated that the timber volume in OGF stands may amount 258 cu.m. per ha, 23 percent belongs to Apitong group (Dipterocarpus spp.), 4 percent Ebony group, 2 percent, 2 percent Nato group, 1 percent Makaasim group and 9 percent from various commercial groups and the rest 61 percent were non-commercial. The area was virgin in terms of the timber resources but not in terms of commercial.