本研究以八卦山臺地之次生林為材料,採用兩個參數之Weibull機率密度函數模擬全林分之直徑分布,並以統計方法之相關及回歸分析,探討Weibull機率密度函數參數與林分性態值、環境因子、生態介量間之關係。結果兩個參數之Weibull機率密度函數可有效模擬試區內林分之直徑分布,且在環境因子中之坡度與坡向會影響直徑分布情形。就林分而言,地理因子中以坡度16°~30°殕眑直徑皆布較為明顯,坡向以NE及SW影響直徑分布較為明顯,而林分性態值及生態介量皆與Weibull函數參數具顯著相關。另在回歸模式所推導的Weibull函數參數值與影響林分結構因子間之關係,在本研究區內可獲得良好的效果。 We studied the natural secondary forest in Ba-Gua-Shan Tableland to investigate its diameter distribution and environmental factors. A model was made by two-parameter Weibull probability density function. The relationships among Webibull function parameter, stand characteristics, environmental factors and ecological parameters were well fitted with correlation and regression analyses. Therefore Weibull function can be applied to model the diameter distribution of the stand in this study site.