The leaf terpenes in Thujopsis dolabrata from all regions in Japan were analyzed using GC and GC-MS. The results show that the major constituents of the diterpene hydrocarbon fraction in this conifer are dolabradiene, hibaene, rimuene, 13-epi-dolabradiene and abietatriene. There were wide variations in the contents of the constituents among individuals and habitats. The results also show that T. dolabrata trees from 34 habitats can be classified into three groups based on the composition of the leaf diterpene hydrocarbon.