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題名 | 紅檜幼齡人工林密度試驗=Studies on Stand Density of Young Red Cypress (Chamaecyparis formosensis Matsum) Plantations |
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作者 | 邱志明; 羅卓振南; | 書刊名 | 臺灣林業科學 |
卷期 | 17:2 2002.06[民91.06] |
頁次 | 頁205-217 |
分類號 | 463.254 |
關鍵詞 | 紅檜幼齡林; 林分密度生長; 競爭密度效果; 自我疏伐曲線; Young red cypress plantations; Stand density; Growth; Competition density effect; Self-thinning curve; |
語文 | 中文(Chinese) |
中文摘要 | 本試驗地位於太平山事業區20林班,造林時.栽植密度為10,000株/ha,株距為 lxlm2,於林齡8年生時,林分已發生嚴重自我疏伐現象,此時7,800株/ha,因此進行5 種密度調整,分別保留10,000(對照區未疏伐8,608)、5000、2,500、1,660及1,110株 /ha,林分調整後10年.發現立木乎均胸徑大小與保留株數多寡成反比,樹高亦有相同趨 勢,林分8-18年生時,以保留2,500-1,660株/ha最佳,最能發揮林地生產力。至18年生 時,10,000株/ha株數自我疏伐比率已達到59.3%,5,000株/ha者為38.7%,2,500株 /ha者為4.3%,1,660及1,110株/ha則尚未發生自我疏伐現象,惟不同密度生長或殘存 株數大小差異之程度,有隨林齡之增加而減少,最後成一致軌跡變化之趨勢。又本試驗以密 度調整後,歷年之生長資料,求出紅檜幼齡林競爭密度效果及收穫密度效果實驗式,並藉發 生自我疏伐之樣區,求出林分最大密度或林分自我疏伐曲線 ν= 93887.54ρ-1.755394(式中ν 及ρ分別代表單株材積及林分每公頃株數),本研究結果可供台灣大面積 |
英文摘要 | The study site for stand density of red cypress (Chamaecyparis formosensis Matsum) plantations is located in compartment no. 20, TaipingMt. Working Circle in the ChilanMt. Area of northern Taiwan. The planted space was 1 x 1 m2. The stand had undergone serious self-thinning at 8 yr of age, so stand densities were adjusted to 5000, 2500, 1660, and 1110 trees/ha, while the control plot had 8608 trees/ha. Mean DBH growth decreased with increasing retention of trees per hectare, and the mean height growth showed the same tendency when the plantation reached an age of 18 yr. However, in a comparison of periodic annual increment at 10 yr after treatment, stand densities retaining 2500 and 1660trees/ha showed the greatest increment in basal area and volume growth. Furthermore, serious competition was occurring in the control plot, and mortality reached about 59.3% because of the self-thinning effect. In addition, mortalities in plots with stand densities of 5000 and 2500 trees/ha were 38.7% and 4.3% after being treated, respectively, but no mortality was found in the plots with 1660 and 1110 trees/ha. However, the above differences between different stand densities should decrease with increasing stand age, and then expected to level off to a constant trajectory. In this report, the reciprocal equations of competition-density effect and yield-density effect were derived from the past 10 yr's growth data after treatment. Moreover, the full-density curve or self-thinning curve on mean stem volume, which shows the upper limit of stand density in regard to arbitrary mean stem volume, is expressed by the equation, ν = 93887.54 ρ–1.755394, where ν and ρ denote the mean stem volume per tree and stand density per hectare, respectively. The results of this study may serve as a useful reference for thinning practices of young red cypress plantations. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。