修枝對紅檜幼林生長及節癒合之研究

Effects of Pruning on the Gowth and the Branch Occlusion Tendency of Taiwan Red Cypress (Chamaecyparis formosensis Matsum) Young Plantations

羅卓振南(Chen-Nan Locho) ； 鍾旭和(Hsu-Ho Chung) ； 邱志明(Chih-Ming Chiu)

《林業試驗所研究報告季刊》 10卷1期 (1995/03) Pp. 41-50

https://doi.org/10.7075/BTFRI.199503.0041

摘要

本研究之目的，在探討紅檜幼林適宜之修枝年齡，修枝高度，以及瞭解修枝傷口之癒合趨勢，以期生產無節大徑材。供試林分為9年生紅檜人工林，幼齡修枝高度係以林木樹高為標準，將修技高度定為樹高之(A)1/3；(B)l/2；(C)2/3；(D)不做修枝之對照組等四種。修枝後6年，結果如次：
1.9年生紅檜人工林若行修枝，其修枝高度以不超逾樹高之1/2處為宜，修枝高度若達樹高之2/3時，則生長不佳，尤以胸徑生長顯著下降。而試驗結果亦顯示，經修枝之林分樹形較完滿，未修枝之林分樹形較尖削，修枝確有助於提高紅檜林分樹幹之完滿度，增加材積生長之效果。
2.本研究探討之紅檜幼齡林，每公尺樹幹著生之側枝約有17枝，側枝節徑分布界於0.2-5.0cm之間，修枝後6年，傷口數癒合率達96%。修枝確有助於無節材之生產。
3.本試驗紅檜人工林，主幹分叉之林木約佔總株數之48%，分叉幹直徑大小界於3.0－11.0cm之間，其中，位於5cm以下者，切口癒台良好，逾7cm以上者，則切口除難以癒合，且產生腐朽缺陷，即使對切口施以油漆或柏油等防腐處理，腐朽依舊發生。因此，進行紅檜修枝，應將分叉幹和側枝分別處理，即切除分叉幹工作，宜於造林後3-5年生時進行，至於側枝則可於9年生時修除。而分叉直徑若已逾7cm以上者，則原則上不應再予修除。
4.紅檜幼林側枝節徑(ND)與修枝傷口癒合時間(T)關係之最佳模式為；(1)優勢木T1-5.7374+19.7199ND-4.2679ND^2+0.4411ND^3及(2)中庸木T2=13.6364+11.5909ND。採用上式推算各節徑修枝傷口之癒合時間，若能配合林分之側技及分叉幹發育狀況，即可釐定最適之修枝林齡。

關鍵字

紅檜 ； 修枝 ； 節徑 ； 形率 ； 癒合

並列摘要

The purposes of this study are to search for the optimum tree age for pruning and the optimum pruning height for young Taiwan red cypress (Chamaecyparis formosensisMatsum) Plantations and to understand the occlusion tendency of branches after pruning. Nine-years-old plantations located at No. 209 Compartment of Chia-Yi Forest District, Taiwan Forestry Bureau were treated by (A) pruning up to 1/3 tree hight; (B) pruning up to 1/2 tree height; (C) pruning up to 2/3 tree height; and (D) no pruning. Six years after treatments the effects of pruning were analyzed and recorded as follows:
1. For 9-years-old plantations the height of pruning should not exceed 1/2 tree height; and when pruned up to 2/3 tree height growth, particularly the diameter increment, of trees decreased significantly. In genreal, stem from of pruned trees is less tapering than the unpruned ones; and pruning, hence, improve the roundness of trees.
2. About 17 branches were recorded for all trees examined; the diameters of these branches were about 0.2-0.5cm. Six years after pruning the percentage of occlusion was about 96%. Pruning, therefore, results in the production of quality wood of high clear length.
3. Fourty eight percent of the trees in all plantations examined showed stem forking. The diameter of these stem forks were about 3.0-11.0cm. When removed, good occlusion was found on stem forks with diameters less than 5cm. On the other hand, if stem forks with diameters greater than 7cm were removed occlusion failed even if preservations treatments were applied. It is, therefore, suggested that, in tending the young plantations of Taiwan red cypress, pruning of branches and removal of stem forks should be carried out independently; the later should be practised when plantations are 3 to 5-years-old whereas the former can be carried out when plantations reach 9-years-old. It is further recommended that removal treatment should not be applied to stem forks when their diameters exceed 7cm.
4. The relationship between the time needed for occlusion (T) and branch diameter can be best illustrated by the following equations:
(1) For dominant trees:
T1=5.7374+19.7199 ND-4.2679ND^2+0.4411ND^3
(2) For intermediate trees:
T2=13.6364+11.5909ND
The optimum age for plantations pruning can be decided by conforming to the development of branches and stem forks and by using these equations.

並列關鍵字

Chamaecyparis formosensis Matsum ； pruning ； branch diameter ； form quotient ； occlusion