溪頭柳杉人工林林下植群恢復研究

Study on the Recovery of Understory Vegetation of Cryptomeria japonica Plantations in Sitou, Central Taiwan

李金玲(Chin-Ling Lee) ； 黃憶汝(Yi-Ru Huang) ； 沈介文(Chieh-Wen Shen) ； 劉婉霞(Wuan-Sia Liu)

《國立臺灣大學生物資源暨農學院實驗林研究報告》 20卷4期 (2006/12) Pp. 299-307

https://doi.org/10.6542/EFNTU.200612_20(4).0006

摘要

臺大實驗林管理處於日據時代引進西川柳杉林進行人工造林後，臺灣開始陸續大規模種植柳杉，而目前臺大實驗林管理處溪頭營林區內之造林樹種仍以柳杉為主，造成林相整齊化、林分結構層次簡單化，以致大幅降低森林生態系原有的生物多樣性，因此在溪頭選定三個不同齡級之柳杉造林地進行林下植被調查，以瞭解人工林現況並推測其未來植群之變化，共設置20m×25m的樣區9個，植相調查記錄到植物共67科123屬161種。
三林分中下層樹種之徑級分布，株數幾乎集中出現於徑級10cm以下，呈現反J形結構。由研究區所出現的枯、倒木之徑級分布可發現皆以10~15cm此一徑級數量最多，顯示林分進入排除期，發生自我疏伐現象，提供耐蔭類幼苗向上生長的空間，有助於針闊葉混合林形成，因此只要冠層有機會疏開，則目前林下之大葉校櫟、紅楠等樹種將有可能發育長至冠層，不過由於目前小苗共同競爭的樹種相當多，可脫穎而出者尚待進一步觀察。

關鍵字

柳杉 ； 林下植群 ； 溪頭

並列摘要

Cryptomeria japonica was massively planted in Taiwan after the Nishikawa cryptomeria japonica introduced and planted in Sitou Experimental Forest during Japanese occupation. Currently, the major afforestation species in the Sitou tract of the Experimental Forest of National Taiwan University are still cryptomeria japonica. All these plantations have a uniform and simplified stand structure with low forest biodiversity. This study investigated the understory vegetation in three different ages of cryptomeria japonica plantations in Sitou to understand the current stand situation and predict population changes. 161 species belonging to 67 families were found in 9 study plots, sized as 20 by 25 meters.
The DBH distribution of the understory vegetation in three stands shows reverse J shape because heights of most individuals were under 10 cm. The diameters of dead woods and fell trees in study plots were in the range from 10 to 15 cm. It indicated that the stands had entered the understory elimination stage, and growing space for seedlings was provided. If the stand canopy were opened, understory vegetation such as Castanopsis fomosana and Machilus thunbergii etc. species might develop to canopy stage. But due to the seedlings competition with various understory species, dominating species are needed to be observed in the future.

並列關鍵字

Cryptoria japonica ； Understory vegetation ； Sitou