本研究主要目的是以多變數法分析楠梓仙溪中上游集水區的森林植群資料。使用降趨對應分析法來呈現70個樣區在空間上的分布情形，並與5項環境因子求相關。結果顯示本研究地區之植物組成與植被類型之空間分布明顯與海拔高及全天光空域有顯著的相關性。植被型之分類使用列表比較法將70個樣區分成3個群團與9個群叢，分別為 (I) 狹葉櫟群團：A.高山新木薑子-赤柯群叢、B.巒大越橘-長尾尖葉櫧群叢、C.大葉石櫟-狹葉櫟群叢、(II) 瓊楠群團：D.柳葉山茶-瓊楠群叢、E.黃杞-錐果櫟群叢、F.山龍眼-細刺苦櫧群叢、(III) 大葉楠群團：G.台灣苦櫧-菲律賓楠群叢、H.香楠-鵝掌柴群叢、I.澀葉榕-大葉楠群叢。

A phytosociological survey was carried out in the middle and upper watershed of the Nan-Tze-Shian stream in southwestern Taiwan in order to determine the relationship between vegetation and environmental factors. Through the use of the tabular comparison method, a hierarchical vegetation classification was established. Detrended Correspondence Analysis (DCA) was applied to the data to clarify the variation of the 70 plots and search for a relationship with 5 environmental variables. The results show that the distribution of vegetation types is responding to the elevation and Whole Light Sky space (WLS). Three alliances and 9 associations were distinguished and described: (I) Cyclobalanopsis stenophylloides alliance, including Neolitsea acuminatissima - Cyclobalanopsis morii, Vaccinium randaiense - Castanopsis cuspidata and Pasania kawakamii- Cyclobalanopsis stenophylloides associations, (II) Beilschmiedia erythrophloia alliance, including Camellia salicifolia-Beilschmiedia erythrophloia, Engelhardtia roxburghiana-Cyclobalanopsis longinux and Helicia formosana-Castanopsis kusanoi associations, and (III) Machilus kusanoi alliance, including Castanopsis formosana-Machilus philippinense, Machilus zuihoensis-Schefflera octophylla and Ficus irisana-Machilus kusanoi associations.