大武事業區臺灣穗花杉健康度評估之研究

臺灣穗花杉為臺灣地區特有種植物，生長環境範圍狹隘且族群數稀少，以小族群分離散布於臺灣中央山脈南端。有鑒於其珍貴及稀少性，因此行政院農委會於1986年正式公告臺東林區大武事業區為「臺灣穗花杉保留區」，借此保護臺灣穗花杉族群留存。本研究利用森林健康指標調查表及因素分析建構臺灣穗花杉的健康指標協助評等與分級。並利用1995及2011年所調查到之臺灣穗花杉胸徑建立林分結構，以瞭解臺灣穗花杉胸徑變化情形，探討設立保留區是否對於臺灣穗花杉健康情形有幫助。本研究結果顯示，7項林木健康指標中能萃取出五個共同因素，分別為樹冠鬱閉指標、樹冠活力指標、根部損傷指標、林木競爭指標及樹冠落葉指標。因素的共同性總和佔總變異的94.76%，具相當高的解釋能力。透過林木健康評分加權平均後，將該區域單株林木健康狀態分為4級；調查結果顯示，臺灣穗花杉處於健康狀態共計113株佔整體48.71%。在臺灣穗花杉胸徑分布及變化情形方面，臺灣穗花杉生長變化不大，直徑分布情形傾向於0－10cm的胸徑範圍內，且株數也都佔了總株數之三分之二以上，生長型呈現反J分布。由調查結果表示將此區劃設為自然保留區具有達到就地保育的成效。此外造成臺灣穗花杉劣化之原因，由實地調查結果判斷為生育環境中林木競爭及地形因子影響最大。

關鍵字

臺灣穗花杉；自然保留區；森林健康指標

並列摘要

Amentotaxus formosana Li is a unique species in Taiwan. The range of the growing environment of Amentotaxus formosana Li is quite limited and there is a very small group separating and dispersing in the south of Central Mountain Range in Taiwan. Due to its preciousness and rarity, the Council of Agriculture has made an official announcement in 1986 that Dawu Working Circle, Taitung Forest District Office, is the “Dawu Taiwan Keteleeria Reserve” in order to protect Amentotaxus formosana Li. The main purpose of this study is to evaluate the health of Amentotaxus formosana Li by using Forest Health Index Survey in Dawu Working Circle. This study further develops the health index of Amentotaxus formosana Li for ranking and classifying with factor analysis approach. Additionally the indexes help us understand and explore the relationship between the health condition and growing environment of the species. The results indicate that there are five common factors extracted by the seven forest health indexes. The five indicators are crown closure, crown energy, root damage, forest competition and crown falling leaf. The above factors can explain 94.76% of the communalities for total variance, and then they are used to classify the tree health. The result of discriminating analysis shows that the rate of predicted classification has a high resolution. By using the weighted mean of the forest health grades, the individual tree health conditions are divided into 4 levels, which are Dieback (first level), Unhealthiness (second level), Deterioration (third level) and Health (fourth level). The results of the study displayed that 48.71% of the Amentotaxus formosana Li living groups is healthy. It indicates the natural Reserve reaches the effect of preservation. Furthermore, two influential factors of the deterioration of Amentotaxus formosana Li are the competition among species in the habitat and the topography.

並列關鍵字

Amentotaxus formosana Li ； Nature Reserve ； Forest Health indexes

國際替代計量

大武事業區臺灣穗花杉健康度評估之研究

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