The study area, PLWS, is located in Loei ProvinceNE Thailand. (Fig.1) and covers and area of about 100km2 with elevation differences between 400 m on thefoot hills and 1600 m on its summit. It is characterizedby a number of hills with a thick sequence of Mesozoicrock of Phu Kradung, Soa Khua, Pha Dua, Phu Phanand Phra Wihan Formations. The areas support twomain forest types: Evergreen and Deciduous forests.The mean annual rainfall of the area varied from1,200 – 1,400 m.m., with over 60% of the annual rainfallfalls in August and September.