老樹是鄉村或都市環境內難得的大樹,民眾與老樹一同成長而關注老樹的健康狀態,但健康是一個抽象的概念,表示健康的因子既互為因果關係又互相影響,使得老樹的健康監測評估有其困難性。本研究欲將影響老樹健康的重要因子歸納出來,以顯示老樹的健康最應注意的面向。以高雄市左營區及屏東北部鄉鎮的茄苳和雨豆樹老樹為對象,藉由觀察及文獻回顧提到的視覺健康指標如樹冠密度、樹冠水平斷面截光率、樹冠枯萎、樹冠退色黃化、莖部萌蘗、地面硬鋪面狀態、開放土壤面積率及樹體腐朽與空洞等,製作老樹健康之視覺指標評估量表進行老樹健康之監測調查,並以因素分析及區別分析評估健康指標之判別力。結果顯示台灣高屏區老樹之健康因素為樹冠因素、養分流通因素及樹體完整性因素等3大主要影響因素,大部分指標之判別力皆具極顯著性(P<0.000),而未來要追蹤高屏地區茄苳老樹的健康狀態以樹冠枯萎及樹體腐朽與空洞即可;高屏地區雨豆樹老樹的健康活力狀態以莖部萌蘗及地面硬鋪面狀態兩指標即可。整體而言,以本研究之方法可達到評估指標簡化之目標。
The old trees are rarities in urban area in Taiwan. Because living together, residents are interest in the old trees’ health condition. But health is an abstract concept. The health variables shown from tree health are not only causal but interactive, it makes old trees health monitoring and assessments would be hard. This study want to generalize the focus health variable of the old trees which would show the most focus factor should be attended. Sampling the old trees of Bischofia javanica and Samanea saman in Zuoying district in Kaohsiung city and northern Pingtung country area by observed and literature reviewed, this study found indicators as crown density, crown transverse plane of foliage transparency, crown dieback, crown leaf discoloration, trunk buds sprouting, land surface pavement condition, open land surface ratio and fungi decay. By making a scale including the visual indicators to assess the old trees’ health, and calculating the discriminate value of the indicators by factor analysis and discriminate analysis. The result shows there are three kinds of the factors as crown condition, nutrient transporting, and fungi decay. Because the discriminate score of most indicators are significant (p<0.000), the result shows we can use indicators as crown dieback and fungi decay to estimate the old trees’ health of B. javanica in Kaohsiung-Pingtung area; in the other way, we can use indicators as trunk buds sprouting and land surface pavement condition to estimate the old trees’ health of S. saman in Kaohsiung-Pingtung area in the future. Overall, we can estimate the old trees’ health by fewer indicators.