Analysis of Changes in First Mode Natural Frequency of Palm Trees Caused by Geometrical and Morphological Aspects

Abstract

Tree is an important part of urban ecology. However, the condition of trees from time to time should be routinely observed in order to avoid the case of falling trees that often take casualties. There are several types of tree defects that can trigger the fall of a tree, such as decay, cancer, crack, etc. So far, there have been several methods to detect such defects as an early indicator of tree condition, for example by acoustic tomography, intrusive indentation, etc. In this study, a detection method is proposed by using natural frequency analysis (modal analysis) of a tree. The selected tree is palm tree. As an initial step, an analysis is required to determine the changes occurring in the natural frequency of palm trees that are affected by, 1) geometric aspects, such as diameter and tree height, 2) morphological aspects, such as the presence or absence of decay and its position on the tree. Natural frequency analysis is done with the help of FEM software. The result shows that the change in natural frequency is not very significant, in the range of 10% to 11%. Therefore, to be able to identify the condition of a tree, further research is needed