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速生桉樹類的耐風育林

Silviculture of Wind-tolerance for Fast-growing Eucalyptus spp

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摘要


於台灣西部地區的雲林縣古坑鄉低蔗產量邊際農地進行玫瑰桉及尾葉桉耐風育林研究,每一樹種重覆三次,每一重覆試區外緣各栽植5行赤桉供作防風林帶,每一重覆面積約為0.55ha。另外設有面積較小無防風林帶的試區6個,做為一般造林的觀察區。本文分析1996年7月31日強烈颱風賀伯(Herb)對造林地所造成的風害損失及18個月後恢復情況。在颱風侵襲下,防風林帶內造林24個月的桉樹林,玫瑰桉有35.9%及尾葉桉58.4%的林木未遭風害:風害後經18個月的恢復生長,即42個月生林分總成活率,玫瑰桉恢復為51.9%,尾葉桉68.6%;同時尾葉桉平均樹高生長10.51m,平均胸徑10.24cm,顯示其初期生長快速且耐風程度較佳,可作為台灣西部邊際農地的短輪伐期造林樹種;而玫瑰桉雖生長亦快,惟耐風力差且受害林木恢復情況欠佳,致風災後全林分成活率偏低,不適合在台灣地區造林:另在未設置防風林帶的一般桉樹造林觀察區中,玫瑰桉嚴重風害的受損木比率(林木折斷、風倒、傾斜嚴重不易恢復生長者)達42%,尾葉桉為38%,相較防風林帶試驗區中,兩樹種僅分別為25%及22.5%屬風害情況嚴重者,其受害林木高出15-17%;再由防風林帶42個月生之赤桉總成活率仍高達 91.7%,顯見耐風力為三種桉樹中最佳者。本研究顯示在台灣西部地區的桉樹造林,由於颱風直接侵襲次數少,可選具高生產力且耐風力較佳之尾葉桉,配合耐風力強如赤桉之桉樹樹種,可藉調整林分結構,減輕颱風對桉樹純林的風害損失,提高邊際農地桉樹造林之生產力。

並列摘要


Wind-tolerance of Eucalyptus grandis and E. urophylla plantations was studied on a marginal sugarcane field in Kukang, Yunlin County, western Taiwan. In July 1994, three 0.55-ha plots were established for each species. In the area surrounding each plot, 5 rows of E. camaldulensis were planted as a windbreak belt. Next to these plots, 6 smaller plots without windbreak belts were planted as general practice areas. The wind-damaged condition and tree growth of plantations were estimated and analyzed in August 1996, immediately after Typhoon Herb assaulted. Right after the measurements, snapped trees were cut at the stem position under the broken height, and uprooted trees were cut at 10-20 cm above ground level. In December 1997, the growth recovery of the plantations was estimated. In these 24-mo-old plantations, 35.9% of E. grandis and 58.4% of E. urophylla trees were not harmed by the violent wind (60m/s maximum) caused by Typhoon Herb. And after 18 mo of regrowth, the total survival rate of E. grandis increased to 51.9% while that of E. urophylla increased to 68.6% with better height (10.51m) and dbh (10.24cm) characteristics of tree growth. This indicates that E. urophylla has a better potential as a fast-growing tree for reforestation programs of marginal farmland in the western region of Taiwan. The early growth of E. grandis also showed its fast-growing potential, but its susceptibility to wind damage and low recovery rates after the typhoon indicate that it is unsuitable for planting in Taiwan. In the nearby general practice areas, percentages of wind-damaged trees in classes of snapped and uprooted stems which could barely not recover their growth reached 42% for E. grandis, and 38% for E. urophylla. On the average, 15-17% more trees suffered from serious wind damage in this area as compared to that in the plantation protected by the belt of E. camaldulensis. At the same time, the survival rate of the 42-mo-old E. camaldulensis windbreak reached 91.7%, showing a much higher wind tolerance than the other 2 species. The results imply that planting highly productive E. urophylla surrounded with high wind-tolerant E. camaldulensis as a windbreak belt can be a possible way to establish fast-growing Eucalyptus in western Taiwan. If coupled with stand planting pattern and density adjustments, the effectiveness of stand stability against strong wind may further increase.

被引用紀錄


陳怡方(2012)。台灣林木生質碳生產的生命週期比較評估〔碩士論文,國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342%2fNTU.2012.01895

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