疏伐對柳杉插條苗與實生苗造林木生長之影響

Influence of Thinning on Cutting Grown Tree and Seedling Grown Tree of Cryptomeria Japonica

王亞男(Ya-Nan Wang) ； 蔡明哲(Ming-Jer Tsai) ； 劉啟福(Chii-Fuw Liou) ； 鄭景鵬(Ching-Peng Cheng)

《國立臺灣大學生物資源暨農學院實驗林研究報告》 23卷4期 (2009/12) Pp. 267-283

https://doi.org/10.6542/EFNTU.200912_23(4).0001

摘要

柳杉於1896年自日本引進台灣後，由於生長快速且良好，因此於1980年代之前的一段期間造林面積逐年增加，是台灣重要之經濟樹種之一。早期柳杉在台灣生育地採種不易，已有多篇與其插條繁殖及造林相關之研究，期望能大量培育柳杉插條苗，以供造林所需之苗木。本研究之目的，在探討以柳杉插條苗與實生苗造林後，不同年齡林木間之生長效應與其差異性，並比較不同疏伐強度對其生長之影響。研究結果顯示：在疏伐前（幼齡期）苗木種類對留存率之影響方面，實生苗林木較插條苗林木佳，但疏伐後，二者則不具差異性。另者，疏伐前苗木種類對平均胸高直徑、斷面積、樹高、材積，雖不具影響，但不同疏伐階段之執行，則對其具有不同之影響。其中，除了初次疏伐後具有較大之影響外，不同之疏伐方式對其影響性尤其顯著，以強度疏伐進行者，可促進林木之最佳生長。柳杉林之經營可施行強度疏伐及多次性疏伐，其目的皆在提高優質林木在全林分中所佔之比率，並改善林分品質，以增加全林最終之經濟穫益。

關鍵字

疏伐 ； 插條苗林木 ； 實生苗林木 ； 柳杉

並列摘要

Cryptomeria (Cryptomeria japonica D. Don.) was introduced into Taiwan from Japan in 1896 and the forestation area gradually increased before 1980 due to their excellent adaptation to the local environment and high growth rate. Eventually, Cryptomeria became one of the most important economic tree species in Taiwan. It was difficult to collect Cryptomeria seeds from the plantation area in the early stage. Accordingly, many researchers in the past made great efforts on the relevant works of cutting propagation and forestation of Cryptomeria in order to cultivate the cutting saplings in a large quantity way and use for forestation. In such circumstances, this study aims to investigate the differences of growth effect of Cryptomeria which were planted by cutting sapling or seed sapling. In addition, a comparison was also made to observe the effect of thinning intensity on the growth characteristics of Cryptomeria. The analysis results indicate that the survival rate of the Cryptomeria planted by seed sapling is better than that planted by cutting sapling. However, after thinning the survival rate were made no difference. On the other hand, although the average values of Diameter at Breast Height (DBH), Basal Area (BA), tree Height (H) and Volume of wood (V) of Cryptomeria are all similar for both sapling types, they are deviated due to different thinning method. In addition to a higher influence on the growth at the initial thinning stage, the thinning methods have crucial effect on the growth of Cryptomeria planted both by cutting sapling and seed sapling. Thinning with high intensity can expedite an optimization of forest growth. For Cryptomeria forestation management, two types of thinning methods can be used, namely, the high intensity thinning and multiple thinning. Conclusively, the main purpose of thinning treatments is to promote the percentage of Cryptomeria stand with superior quality and finally increase the economic benefit of entire forest.

並列關鍵字

Thinning ； Cutting grown tree ； Seedling grown tree ； Cryptomeria japonica