太行山南麓天然次生林之樹種組成和環境梯度分析

Tree Species Composition and Environmental Gradient Analysis of a Natural Secondary Forest on Southern Taihang Mountain

趙輝(Hui Zhao) ； 王齊瑞(Qi-Rui Wang) ； 宋國華(Guo-Hua Song)

《台灣林業科學》 32卷3期 (2017/09) Pp. 223-235

https://doi.org/10.7075/TJFS.201709_32(3).0004

摘要

太行山原始林長期受皆伐破壞，森林覆蓋率由20～40% (8000 B.C.)降到不足5% (A.D. 1950)，與海拔較高的山區相比，太行山低山丘陵區的森林曾經受到更嚴重的破壞。我們在太行山南麓與黃河北岸之間的濟源市調查了24個20×20 m天然次生林樣區的樹種組成及13個環境變數，並利用主成分分析探討群落組成和環境因數間的關係。結果顯示，變數對樣區生境差異的影響排序為：海拔＞土壤電導率＞土壤pH值＞土壤容重＞土壤孔隙度＞土壤全氮含量＞土壤有機碳含量＞坡位＞土壤含水量＞坡向＞坡度＞土壤深度＞碎石體積百分比；調查記錄31個樹種，其中野皂莢、橿子櫟、黃櫨、栓皮櫟、欒樹是對群落差異貢獻最大的5個樹種，也是17個樣區的優勢種。Ward聚類將樣區分為4種類型，分別沿海拔和土壤養分兩個梯度發生變化。太行山南麓次生林物種－環境關係與中段、北段相比差異明顯，南麓植被恢復處於相對早期階段，在此進行植被重建和恢復時應充分考慮地形差異，尤其是海拔和坡位的影響與制約。

關鍵字

主成分分析 ； 天然次生林 ； 太行山南麓 ； 梯度 ； 低山丘陵區

並列摘要

The forest cover rate of Taihang Mountain had dropped from 20~40% (8000 B.C.) to ＜ 5% (A.D. 1950). Compared to the forest higher up on the mountain, the forest on hilly land of Taihang Mt. has been seriously destroyed. We investigated 24 quadrats (20×20 m) in JiYuan City, which covers typical secondary forests types of southern Taihang Mt. We used a principal components analysis (PCA) to analyze environmental data and Hellinger pre-transformed species data, and used the Kaiser-Guttman criterion to decide how many axes are worth representing and displaying on the basis of the amount of variance explained. Two biplots were produced in scaling 1 (optimal display of quadrats) and scaling 2 (optimal display of variables). All 13 variables were sorted by their contributions: elevation ＞ electric conductivity ＞ soil pH ＞ bulk density ＞ pore space ＞ total N ＞ organic C ＞ topography ＞ moisture content ＞ aspect ＞ slope ＞ soil depth ＞ gravel volume percent. Ward's minimum variance clustering results showed that vegetation types varied along elevation and soil nutrient gradients. Gleditsia microphylla, Quercus baronii, Cotinus coggygria, Quercus variabilis, and Koelreuteria paniculata were 5 species with the largest contributions among all 31 tree species to community variety. This result agrees with reality as these 5 species were dominant species in 17 quadrats. The species composition has been largely affected by the topographical gradient, and has been less affected by the nutrient gradient.

並列關鍵字

PCA ； natural secondary forests ； south of Taihang Mountains ； gradient ； low mountains and hills