Many Collembola live in the soil, and the spatial structure of the soil is one of the key factors determining the density of Collembola. It also live on the tree, and it is probable that spatial structure of tree bark influence the density of Collembola in the arboreal environment.

Study　was conducted in a wood land adjacent to the campus of Ryukoku University Seta,Otsu,Shiga,Prefecture during June-November 2011. A total of 74 trees treated were Pinus.densiflore,Quercus.serrata,llex.pedunculosa,Eurya.japonica and Chamaecyparis.obtuse. Collembola of the arboreal environment was collected by cloth trap on the tree bark surface.The uneveness of bark structure was measured for each tree species.

Uneveness of bark surface was significantly different between tree species: that of P.densiflore and Q.serrata were larger than that of l.pedunculosa,E.japonica and C.obtusa. Density of Collembola was, however, showed no significant difference between tree species.

Further analyses will be present on the relationships between the density of Collembola and the arboreal environment.