| Summary: | 碩士 === 國立宜蘭大學 === 自然資源學系碩士班 === 94 === The study is involved with the investigation towards the coastal protection Casuarina forest in Northeast Taiwan(Fulung、Yi-lan and Hualien). The systematic sampling method is used to locate sampling bends with 1km interval and results 30 sampling bends with Casuarina.spp. Depending on the size of the stand, each sampling bend, takes from the main Casuarina silvicultural boundary line near the sea, and then acrosses the stands. The plots on each bend are divided into the inner, middle and outside sampling plots. They are separated by 40m and each sampling plot is 0.02 ha. A total number of 57 plots has been established and all trees wihtin each plot have been measured with those variables related to their health. Factor analyses are applied to construct the health indicators to make the classification of tree health easier, and discriminant functions are also constructed to predict the conditions of tree health to understand the health conditions about Casuarina among areas.
After the application of factor analysis those health-related variables have been classified into two factors:『crown damage indicator』 and 『foliage vigor declining indicator』. The above two factors can explain 81%(5.67/7)of the communalities for total variance, and then their scores are used to classify tree health.The result of discriminant analysis shows that the hit rate of predicted functions is very precise. The hit rate of using the seven original observed variables is 95%, and the hit rate of using three of those variables can be above 90%.
The above procedure can not only construct health indicators of Casuarina trees, but also evaluate the health conditions of stands at the same time, and then the manager can proceed the stands conservation and management with the objective and effective methods.
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