恆春海岸地區銀合歡移除造林初期之苗木生長表現

Growth performance of seedlings at the early stage of afforestation on removal of Leucaena leucocephala (Lam.) de Wit in Henchun coastal area

銀合歡入侵已造成恆春半島海岸林生態系的嚴重衝擊。本研究為探討恆春地區不同海岸林生育地銀合歡移除造林後之苗木初期生長之表現，以屏東林區管理處2015年進行銀合歡移除造林之海口海岸造林區、小尖山海岸造林區及小尖山山坡造林區為研究區，於各造林區中各設置3個0.05 ha之調查樣區，進行土壤及造林苗木之生長調查，以各樹種苗木之高生長、地徑生長、健壯指數及枯死率並配合土壤性質，以變異分析探討各造林樹種苗木之生長表現，及其與土壤性質之關係。研究結果顯示海口海岸造林區因土壤質地屬於砂質土，土壤保水力較差且土壤相對貧瘠，6種造林木（木麻黃、欖仁、相思樹、台灣欒樹、黃槿及水黃皮）之生長表現較差，與小尖山海岸造林區（壤質砂土）及小尖山山坡造林區（黏壤土）有顯著差異，利用各樣區之健壯指數及成活率，以群集分類探討造林樹種對不同生育地的適生性分析，結果顯示黃槿適生於砂質土的海口海岸造林區；欖仁、水黃皮、黃槿適生於壤質砂土的小尖山海岸造林區；而欖仁、臺灣欒樹、黃槿適生於黏壤土的小尖山山坡造林區。 The invasion of Leucaena leucocephala (Lam.) de Wit had caused the serious impact of the Henchun coastal forest ecosystem. In this study, we used Haikou Coastal Afforestation site, Xiaoxian Coastal Afforestation site and Xiaoxian Hillside Afforestation site which would be removal L. leucocephala and afforestation by Pingtung forest district office in 2015. Three 0.05 ha sampling plots were set up in each afforestation site. The soil properties and seedlings height, diameter at above ground, sturdiness quotient and survival rate were investigated after 18 months of afforestation. The seedlings growing performance and relationship between soil properties were been explored by variance analysis. The results showed that Haikou coastal afforestation site, the soil texture belong to a sandy that had poor soil water retention and barren, the six afforestation species (Casuarina equisetifolia L., Acacia confusa Merr., Terminalia catappa L., Pongamia pinnata (L.) Pierre, Koelreuteria henryi Dummer, Hibiscus tiliaceus L.) were a significantly poor growing performance with Xiaoxian Coastal Afforestation site(loamy sand) and Xiaoxian Hillside Afforestation site (clay loam). The sturdiness quotient and survival rate of all species in each study site were analyzed using cluster analysis so as to fit growing adaptability for each site. The results showed that Hibiscus tiliaceus L. would be suited for Haikou coastal afforestation site, Terminalia catappa L., Pongamia pinnata (L.) Pierre, Hibiscus tiliaceus L. be suited for Xiaoxian Coastal afforestation site, and Koelreuteria henryi Dummer, Hibiscus tiliaceus L., be suited for Xiaoxian Hillside afforestation site.