相思樹人工林自然演替之研究－以中國文化大學華林實驗林為例

The Study of Natural Succession of the Man-made Forest of Acacia confusa in Hwa-Lin Experimental Forest of Chinese Culture University

徐寶琛(Pao-Chen Hsu)

《華岡農科學報》 11期 (2003/06) Pp. 85-106

https://doi.org/10.29985/HKJA.200306.0007

摘要

本研究係以中國文化大學華林實驗林場的相思樹造林地為研究對象，了解其在經過30年後逐漸自然演替成天然林的各項可能因素、機制。經調查後發現當地原生樹種如水金京、江某、紅楠、白匏子、香楠、裡白饅頭果、小梗木薑子、台灣山桂花、森氏紅淡比、台灣桫欏與烏心石入侵相思樹造林地內，而有逐漸自然演替成天然林的跡象。為了解大徑相思樹逐漸被入侵的原生植物取代之現象，於是調查相思樹造林地中相思樹與入侵原生植物的相關性，並在林內設置採集網及收集林內地表層土方，進行種子雨、種子庫收集及觀察。由相思樹林內入侵的原生植物調查知，其更新無礙。而由種子雨及種子庫的觀察知相思樹的天然下種及初期發芽率均高，但日後因其他植物的快速生長所造成的蔽蔭令種子庫內已發芽生長的相思樹苗死亡，此即導致相思樹造林地內無相思樹小徑木而逐漸被入侵原生植物取代之原因。依Simpson's的歧異度公式計算試區的歧異度為0.743，可見已是歧異度高之林分。另重複分別進行相思樹之環狀剝皮、伐除、整地且以當地原生植物之幼苗造林等干擾處理，以觀察不同干擾對相思樹造林地演替之影響。經1999年、2000年、2001年的追蹤調查知陽性的阿薩姆茶，在相思樹環剝後胸徑有明顯增加的趨勢。而整地造林若不撫育，一年後成活率僅30%左右，即栽植的228株中存活者僅73株，但入侵此二樣區中的原生植物，合計卻高達46株，且與地被植物栗蕨形成完整的地被覆蓋。

關鍵字

相思樹 ； 人工林 ； 原生植物 ； 自然演替

並列摘要

The man-made forest of Acacia confusa in Hwa-Lin Experimental Forest of Chinese Culture University has been changing to a natural forest gradually because of the native species moved in by wind and even regenerated very well in the past 30 years. After investigating and calculating the data of 8 plots, the Simpson's diversity is 0.743 and the first of IVI is A. confusa. Meanwhile we found that the D.B.H. of all A. confusa was large, from 19.1cm to 35.9cm, no small one; but the regenerations of native species were good, the D.B.H. including large and small. To study the relationship between natural regeneration of native species and there seeds in soil, we collected seed rain and observed the germination of seed bank. In the beginning there were many seedlings of A. confusa, but two years later when some native species grew faster than A. confusa and made more shade, A. confusa seedlings died. The phenomenon explains why there are no small A. confusa in man-made forest of A. confusa. So A. confusa wll be replaced by native species and become a high diversity natural forest in the furture. Seventeen months after first investigation, we repeated three kinds of interferences on different plots: to cut off the bark 20cm wide around the stem of A. confusa in, or to cut down A. confusa, or to clear the plots and to plant native species seedlings collected from the site around plots. One year after interferences, the results showed: (1) the sun plant-Camellia sinensis var. assamica grew fast because the shadow of A. confusa was removed, (2) the native species invaded by wind or run-off grew faster than the seedlings planted without any tending artificially.

並列關鍵字

Acacia confusa ； man-made forest ； native plant species ； natural succession