- 期刊
以目視樹木評估法判斷中國文化大學之校園樹木健康風險
Using the Visual Tree Assessment (VTA) Method to Evaluate Tree Health Risks on the Chinese Culture University Campus, Taipei, Taiwan
摘要
在校園中人們為了環境綠化而種植許多的樹木，但常常因為不當的修剪或者其他因素造成樹木的斷裂或倒塌，嚴重時會造成建築物的損壞或危害師生的安全，因此定期執行樹木健康評估可以預先防範以降低樹木傾倒的風險。本次調查使用目視樹木評估法（VTA法）對中國文化大學校園樹木進行非破壞性檢測，利用評估表對樹木的根部、冠層狀態、樹冠密度、活冠層比例、樹冠有無梢枯進行健康度評分，依綜合評分將樹木的安全度分為低風險、中度風險、高風險、極端風險4個等級。本次調查了20種樹種共111棵樹。調查結果顯示數量最多的是龍柏，最少的是朴樹、羊蹄甲、杜英、青楓、艷紫荊與樹杞，低風險的樹木有4棵佔4%，中度風險的樹木有97棵佔87%，有高風險與極端風險的樹種共10棵佔9%。根據調查結果極端風險的樹木是大仁球場的龍柏與曉園的黃連木，而校園中使樹木健康有風險的因子為風力，造成樹幹傾斜加上樹冠偏側與不當修枝，使樹木的危險度提高，因此有倒伏危機的樹木應該利用支柱或引索固定並配合適當的修剪以減少載重，避免不當修剪，才能使樹木長期保持良好的健康度。
並列摘要
Many trees have been planted on the Chinese Culture University campus for environmental greening. However, improper pruning and other factors may cause trees to fracture or collapse, in serious incidents causing damage to buildings and threatening the safety of students. Therefore, regular implementation of tree health assessment can reduce the risks of treefall incidents. In this study, trees on campus were surveyed using a non-destructive visual tree assessment (VTA) method. According to a comprehensive scoring system, the degree of safety of trees was rated as low, moderate, high, or extremely high risk based on roots, canopy state, canopy density, live canopy ratio, and whether or not the canopy was dry. The survey covered 111 trees in 20 species. Results of the survey showed that the greatest number of trees were Chinese juniper (Juniperus chinensis cv. Kaizuka), and the fewest number of trees were Chinese hackberry (Celtis sinensis), orchid trees (Bauhinia variegata), common elaeocarpus (Elaeocarpus sylvestris), Oliver’s maple (Acer serrulatum), Hong Kong orchid trees (Bauhinia × blakeana), and coralberry/marlberry (Ardisia sieboldii). Four trees (4%) were rated as low risk, 97 trees (87%) as moderate risk, and 10 trees (9%) as high or extremely high risk. Based on results of the survey, extremely high risk trees were Chinese junipers at the Da Ren basketball and volleyball courts and Chinese pistache (Pistacia chinensis) at the Xiao Gardens. The tree health risk factors on campus include wind, resulting in tilted trunks and crowns, and improper pruning, such that tree risk increases. Therefore, support pillars or cords should be used to stabilize trees at risk of falling, in combination with appropriate pruning to reduce weight loading and avoidance of improper pruning, thus maintaining long-term good health of trees.