• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.42 no.3
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• pp.42-50
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• 2024

This study aims to develop a method for assessing the structural stability of large-old trees, which are typically evaluated primarily for their physiological health. To achieve this, finite element analysis(FEA) was applied to Zelkova serrata (Thunb.) Makino, which are significant as natural monuments, protected trees and street trees in urban areas and parks. Four representative large-old trees in Buyeo-gun, which had undergone surgical treatment, were selected for creating analytical models and being conducted FEA. The key findings are as follows: first, we made 3D models by acquiring 3D scanning and ultra sonic tomography data for analyzing FEA. We proposed methods for constructing 3D meshes and calculating self-weight and wind loads based on tree shape to interpret FEA. Second, the study confirmed that wind loads increase proportionally with the size of the tree and the shape of the canopy. Wind loads were observed irregularly in cases of unusual shapes or multiple segments of the canopy. Third, FEA's result of large-old trees with decay-induced cavities indicated that even under strong winds (70m/s) from typhoons, the likelihood of damage from trunk breakage due to self-weight was relatively low. Fourth, decay-induced cavities were found to affect internal stress distribution, leading to structural weaknesses. This highlights the need for measuring and documenting the shape of cavities during tree assessments. Accurate measurement and documentation of branching and tree form are also crucial, as complex branching and cavities increase the likelihood of structural weaknesses. The study also identified limitations in estimating self-weight, transmissivity, and projected areas of the canopy based on wind direction. To improve the accuracy of FEA, the method for enhancing precision of the 3D model and measuring the canopy and is necessary.