Via the stepwise discrimnant analysis, crown dieback is found to be the most important variable.If one wants to keep the hit rat over 90%, one can use 6 original observed variables.

• 使用逐步鑑别分析，发现树冠梢枯为最重要的变数，而将调查变数缩减为6个仍保有90%25以上的击中率。