台灣中部地區天然林林分結構及其生長之研究

Abstract

本研究以大雪山及鳶峰地區天然林為對象，大雪山地區調查所得 資料 以 Weibull機率密度函數分別模擬林分及樹種之直徑分布，並以 相關及回 歸分析探討 Weibull函數參數與生態介量、環境因子間的關 係並以曼．惠 內 U統計量分析不同環境因子間同一樹種蓄積量之差異 情形。鳶峰地區則 以二次調查之資料，進行生長關係之探討，其結果 如下： 1.兩個參數之 Weibull機率密度函數可有效模擬試區內之林分 及樹種之直 徑分布。 2.研究區之歧異度指數在0.71∼1.06之間， 且植物種數與平均個體數的關 係呈反 J形分布。 3.就林分而言， 地理因子中以海拔高影響直徑分布較為明顯且其 Weibull 函數之 b 、c 值有隨海拔高的增加而下降趨勢，而林分性態值及生態介 量皆 與 Weibull函數參數具顯著相關。 4.由逐步回歸模式推導之 Weibull 函數參數值與影響林分結構因子間之關 係為： b=0.9823+0.9877D-0.0044V c=4.8699-0.0022A-0.0104D+0.0008 V+9.3630Si-6.4670E-3.3369Sr ?註：A:海拔高度，D:平均胸徑，V:每 公頃材積，Si:Simpson''s歧異度， E:均勻度指數，Sr:種類豐富 度) 5.於鳶峰樣區天然林生長之研究中，經二次調查16年期間材積量增 加189. 3167立方公尺/ha ，株數則減少17株/ha ；而生態介量以第 一次調查之 種類豐富度及歧異度指數較高，均勻度則以第二次調查 較高。

The natural forest in TaHsueh-Shan and Yuanfeng Areas are the objects of this study.For the investigation of natural for- est in TaHsueh-Shan Area,it''s to simulate the diameter distrib- ution of stand and species separately by two-parament Weibull probability density function;to explore the relation of Weibull function paraments with ecological paraments and environmental factors by correlation and regression analysis and to analyze the discrepancy of growing stock for identical tree species am- ong different environmental factors by Mann-Whitney U-test ana- lysis.The results got from the exploring of growing relation on the natural forest of Yuanfeng Area by two time investigation are as follows: 1.Diameter distribution of stand and species is effectively si- mulated by two-paraments Weibull probability density function. 2.The Diversity index of study area is between 0.71 and 1.06 in the area, it presents opposite J-type distribution between p- lant species and mean individual. 3.For stand, altitudes is the obvious factoe to effect diameter distribution in all geographic factors and c-value and b-value of two-paraments Weibull probability function are decreased by increasing the altitudes gradients.The notable correlation of Weibull function paraments with stand characteristics and ecological paraments is established. 4.The correlations between Weibull function paraments and infl- uential factors of stand structure by regression analysis are: b=0.9823+0.9877D-0.0044V c=4.8699-0.0022A-0.0104D+0.0008V+9.3630Si-6.4670E-3.3369Sr 5.In the study of natural forest growing in Yuanfeng Area, it shows that the volumes increase 189.3167m /ha but plants decr- ease 17 in number by two time investigations on the period of 16 years.At the first investigation, the Species richness and Diversity index of ecological parament are higher but at the second investigation, the Evenness index is higher.