The dieback of C.japonica is extended over a wide range (more than 5000 km 2 ) covering the western and north western regions of Japan's Kanto District. The affected area was compared with normal areas concerning density of S0 2 , N0, N0 2 and photochemical oxidant mixtures(Ox) in the atmosphere and the amount of acid deposition. As a result it is inferred that acid deposition and oxidant are the principal causes of large scale dieback of C.japonica in the Kanto District.

No abstract