臺東知本地區海岸造林樹種生長表現—以木賊葉木麻黃、黃槿、垂榕、檸檬桉為例

In this study, 4 species of planted trees are investigated. (Casuarina equisetifolia Forst. , Hibiscus tiliaceus L., Ficus benjamina L. var. benjamina and Eucalyptus citriodora Hook.). This research focuses on coastal area soil nutrition and planting environment. Differences in growth rate and relevant soil elements in the spring and autumn seasons are discussed. The results of the study are expected to provide important information for choosing tree species or carrying out planting of mixed forest in coastal areas. Tree leaf nutrient and soil analyses were carried out to understand tree leaf nutrient content relevant to seasonal change and growth rate. We sampled tree leaves between April and May 2007 (spring season) and between November and December 2007 (winter season). In addition, soil samples were obtained from the same area. The results showed that the soil in the sampling area is alkaline and is of poor quality in terms of nutrient content. We also analyzed the nutrient content of the tested leaves. Results showed much higher quantities of nutrients in autumn than in spring, except for phosphorus in E. citriodora and H. tiliaceus, calcium in H. tiliaceus and C. equisetifolia, and magnesium in E. citriodora. The trend in micro elements differed from that of mass elements in the spring. In terms of height of the trees, E. citriodora showed the best growth rate, followed by C. equisetifolia. In terms of diameter, H. tiliaceus showed the best growth rate followed by E. citriodora. E. citriodora had more mass elements in autumn than in spring except for phosphorus. C. equisetifolia had higher quantities of elements in autumn than in spring except for calcium. A major species of planted tree in coastal areas is C. equisetifolia. It showed the lowest quantities of mass elements during the spring, followed by E. citriodora. Lower quantities of nutrients were found in aged leaves, implying that nutrients had migrated to other parts of the tree. This is an adaptation of trees growing in poor soil. Keywords: nutrient analysis, seasonal change, growth.