Using suballiances of the Machilus-Castanopsis forest zone to delimit the geographical climatic regions of Taiwan

Tze-Ying CHEN1, Tzung-Tai HUNG1, Ching-Feng LI2 & Chiou-Feng YU3
1 Department of Forest and Nature Resources, National Ilan University, Ilan, Taiwan
2 Department of Botany and Zoology, Masaryk University, Brno, Czech Republic
3 Department of Sience and Technology, Council of Agriculture, Executive Yuan, Taipei, Taiwan

Horng-Jye Su analyzed the weather stations in Taiwan to group them into geographical climatic regions. The amount of water deficiency and the duration of dry season had been considered in the analysis. The result divided the geographical climatic regions into 7 parts: northeast region, northwest region, central west region, southwest region, southeast region, east region and Lanyu region. The first two regions were of everwet climate type, while other regions showed various degrees of summer rain type (monsoon climate). Then compared with the altitudinal vegetation zones we found that the Machilus-Castanopsis forest zone were widely distributed in Taiwan, resulting in the division of the geographical climatic regions more clearly than the other zones. We analyzed the data of 2 286 plots for vegetation classification of Machilus-Castanopsis forest zone in Taiwan. The vegetation classification results in 47 subassociations and 18 associations, which can be grouped into 8 suballiances, including Schimenion kankaoensis, Neolitsenion parvigemmae, Ormosienion formosanae, Castanopsenion sessilis, Turpinienion ternatae, Ficenion irisanae, Litsenion acuminatae and Dendrocnidenion meyenianae. The first five suballiances belong to mid-slope and ridge type, and the last three alliances are a valley type. This study found that the alliances of the valley type are evenly distributed in Taiwan, including Ficion irisanae, which are distributed in the northeast region, northwest region and central west region; Litsion acuminatae are evenly distributed in Taiwan; Dendrocnidion meyenianae are distributed in the southwest region, southeast region and east region. But the suballiances of mid-slope and ridge type can be used to divide Su’s geographic climatic regions clearly. Castanopsenion sessilis are distributed in the Northeast region, Ormosenion formosanae in the Central west region, Turpinienion ternatae in the East region, Neolitsenion parvigemmae in the Southwest region, and Schimenion kankaoensis in the Southeast region and Hengchun Peninsula.

© 2012 Organizing Committee