(1) The writer gave a brief interpretation of the previous discussions. concerning the occurrence of Raingreen Forests in Formosa. (2) The macroclimatic condition of Formosa is outlined, and is expressed severally by the KOPPEN'S climatic formulae (Fig. 1.) It is discussed that how much has the macroclimatic condition acted upon the development of vegetation in Formosa. (3) Judging from the Awa Climate recognized in the south-western part of Formosa, the woods in this area presumably correspond with the Raingreen Forest type. It is, therefore, small wonder to think that the woods in this area may be a climatic climax. (4) The Albizza procera-Bridelia monoica association (Fig.2., Tab.3.) of Raingreen Forests and the Bombax Ceiba-Imperata cylindrica association of Savannah Forests, both of which grow in this area, are explained.