天然檜木林擇伐更新之研究

Natural Regeneration of Cypress Old Growth by Selective Cutting and Intensive Site Preparation

羅卓振南(Chen-Nan Locho) ； 鍾旭和(Hsu-Ho Chung) ； 邱志明(Chin-Ming Chiu) ； 周朝富(Chao-Fu Chou) ； 羅新興(Shin-Shing Lo)

《林業試驗所研究報告季刊》 4卷4期 (1989/12) Pp. 197-217

https://doi.org/10.7075/BTFRI.198912.0197

摘要

本研究乃就大溪事業區第52林班及94林班之保安林區，本所原實施單株擇伐試驗之天然檜木林，繼續進行天然更新整地處理試驗，以探討整地方式和擇伐強度對下種更新之效應，同時對撫育成本，以及保留木和地被植物之生長情形亦調查進行分析。將整地處理分為：(A)集約中耕整地；(B)粗放整地；(C)未整地等三種。整地後12年之結果要述如次：
本試驗結果顯示，天然下種更新之林地整治方式，以集約中耕整地掘除什草根部者最為有效，其下種稚樹之數量最多，分佈均勻，能完成預定目標90%之更新，生長亦較快速。粗放整地和未整地者，稚樹分佈極不均勻，僅能分別完成預定目標之35%及32%之更新。
本研究實施之各種擇伐度均能達到誘導天然下種之效應，惟擇伐度之強弱與下種稚樹之多寡無關，但強度和中度擇伐者，稚樹之生長較為快速。
天然檜木林每隔3～5年才大量結實一次，整地時期須與結實年度相互配合，以確保下種更新之成功。
天然下種之稚樹於幼齡期生長較慢，必須實施集約撫育工作，以促進幼樹生長。
採單株擇伐作業，必須具備豐富的經驗和熟練的技術。為避免保留林木發生嚴重風倒或枯死，應避免施行極強度擇伐，集材作業必須採架空線集材，在地形地勢陡峻之地區應力求避免實施單株擇伐作業。
本試驗集約中耕之整地和撫育作業，每公頃所需之工作天數為124工，要較一般皆伐跡地造林之178工為低。

關鍵字

天然檜木林 ； 單株擇伐 ； 天然下種更新 ； 橫坡帶狀 ； 集約中耕整地 ； 臺灣扁柏 ； 紅檜 ； 稚樹

並列摘要

The effects of selective cutting and site preparation intensities on the regeneration of old cypress stands were studied on the compartments 52 and 94 of the Ta-Chi Circle. Three different intensities of selective cutting which represent the removal of 40-45% B. A. (heavy), 30-35% B. A. (medium) and 20-25% B. A. (weak) of the old growth were applied to the stands. The regeneration sites were treated as follows; (A) intensive preparation followed by scarification; (B) gross prepartion; and (C) Without any preparation (or the control) Twelve years after site preparation treatment the results of natural regeneration were surveyed and analyzed. They can be summarized as follows:
1. Intensive and scarified method was found to be the most effective for the regeneration of cypress. Seedlings found in sites prepared by this method not only performed better but also occured in larger quantity and distributed more evenly than those found in sites prepared by other methods.
2. All selective cutting intensities used in the present study could lead to the success of natural regeneration. Cutting intensities did not affect number of seedlings which occured on the sites; they did, however, affect the growth rate of regenerated seedlings viz. seedlings found in areas of heavy and medium selective cuttings performed better than those found in areas of week selective cutting.
3. The corn crops of cypress trees fruit abundantly every 3 to 5 years. To assure the success of natural regeneration, it is suggested that, timing-wise, sites should be prepared in accordance with the cycle of corn setting.
4. During the early stage of development of naturally regenerated seedlings, intensive tending should be taken to improve the growth of the seedlings.
5. Experience and skillfulness are indispensable to the sucess of selective cutting operations. Over-intensive selective cutting would result in the wind throw or dieback of the remaining trees; and therefore, stould be avoided. For logging operations high-lead cable logging system is recommended for the same reason; In rugged areas, selective cutting operation should be avoided.
6. The labors needed for applying intensive and scarified preprartion method to selective cutting sites were 124 man-days/ha, which was lower than that needed for applying the same method to clear cutting sites.

並列關鍵字

Natural cypress stands ； Single tree selection cutting ； Natural regeneration ； Horizontal strip ； Intensive site preparation ； Taiwan cypress ； Taiwan Red cypress ； Seedlings