A safety factor of old trees Pterocarpus indicus Willd. in Bogor Botanic Gardens

Abstract

Trees have a vital role in human life, including as a part of the urban forest area. The tree health assessment is an important activity to support tree safety and stability in an urban forest. Bogor Botanic Garden is the most extensive botanic garden in Indonesia, with a large collection. The study aims to determine the health condition of old trees (Pterocarpus indicus Willd.) in the Bogor Botanic Gardens and measure the safety factor’s magnitude. The method used was an evaluation generated based on a sound velocity from Arborsonic’s tool. The measurement of appearance parameters was carried out to complete the information in determining the biomechanical strength of the tree. Four large and old trees, about 170 years old, were chosen in this study. The results showed that decay to hollowness in the trunk varied from 4% to 58%. The biomechanical analysis calculates the safety factor and t/R ratio, revealing that one tree had moderate risk and others possessed low risk. Further investigation to ensure the tree condition should be carried in terms of risk mitigation of tree management.