JEF is located in Jeju Province which is the biggest island in Korea. 
Jeju island belongs to warm temperate forest zone and offers very unique natural landscapes because Mt. Halla(1,950m ASL), the highest mountain in South Korea, creates various forms of habitats along the altitudinal gradient from evergreen broadleaved species in the coastal area to subalpine species around the mountain peak. 
Mean temperatures of January and July are individually 2.4℃ and 24.9℃ and annual precipitation reaches about 1,457mm. 
There still remains many evergreen broadleaved species but their coverage is not so high because most of the forest area except for higher area experienced disturbances such as pastureland development and timber harvest for mushroom production. 
1ha permanent plot was established in 2004 Major tree species of JEF are composed of Quercus acuta, Camellia japonica, Carpinus laxiflora etc. 
Stem densities of evergreen broadleaved trees and deciduous trees over 2cm in DBH were individually 4,078 trees/ha and 1,703 trees/ha and the basal area were individually 28.4㎡ and 13.8㎡.