本研究於臺灣省林業試驗所六龜試驗林進行,調查並分析因民國72年所實施的林相改良先趨計畫作業,對臺灣南部低海拔闊葉林之植群組成、歧異度、密度-徑級分布,以及各優勢樹種之族群結構,所造成的影響。研究結果顯示:林分之歧異度隨干擾之增強而有降低的趨勢,優勢度則相對提升,林分間的相似性以輕度及中度干擾區間較高。利用徑級-密度分布曲線,分析各樣區之林分結構發現,輕度及中度干擾區之林分結構均為反J型分布,而強度干擾區,則呈鐘型右偏歪之分布,各區主要樹種之族群結構亦各有差異,於強度干擾區及輕度干擾區呈鐘型右偏歪之分布,於中度干擾區,則呈倒J型分布,本研究發現:適當的人為干擾,例如林地除草配合整理伐,可能有助於上層林木之天然更新,並調整林分發育之方向。
Floristic composition, and population structure of stands were studied in lower altuitude broad-leaved forest along different gradients of disturbance which resulted from the stand improvement operation in 1983, in Liu-kuei experimental froest, Taiwan Forest Research Institude, southern part of Taiwan. Tree species diversity declined while dominance enhanced with increasing disturbance. Effects of disturbance on the population structure of stands and dominant tree species were analysed by density-diameter curves. Stands and dominant tree species under weak and mild disturbance always show mound shaped and positively skewed or reverse J-shaped curves while intensively disturbed stand shows mound shaped and positively skeweddistribution. The results of this study shows disturbace under control (weeding/salvag cutting) could stimulate natural regeneration of conopy trees, and regulate the direction of forest development.