Stand-scale leaf area index (LAI) characterizes the canopy structure for estimating GPP and transpiration in closed forests. In natural forests, uneven distribution of trees causes heterogeneity in forest canopy and also spatial fluctuation in LAI. In this study, we detected spatial distribution of trees and spatial variation in LAI in Yamashiro Experimental Forest, deciduous-evergreen mixed forest on the complex terrain. Deciduous trees were relatively distributed in ridge line and evergreen trees were relatively distributed in valley line. Uneven distribution of tree species should cause heterogeneity in canopy structure. To detect the heterogeneity in canopy structure, we measured local LAI using hemispherical photographs along the ridge-valley line transection (190.2m). We took 380 photographs in 4 minutes to prevent the change in sky condition once a week. Compared with the LAI-2000 (Li-cor), measurements by hemispherical photographs could detect spatial distribution of LAI even for a small gap. In winter, the peaks in LAI by evergreen trees were isolated each other along the transection. After the foliation of deciduous trees, crowns were connected and LAI ranged 2-4 continuously except in small gaps regardless of the species. The proportion of continuous canopy and gap within a forest can be described by the local-scale LAI measurements.