Judul: Health, Biomechanics, and Root Architecture of Large and Old Dipterocarp Trees in the Urban Landscape of the Bogor Botanic Gardens
Abstrak: Large and old trees play a pivotal ecological role within the ecosystem by offering crucial habitats for fauna and epiphytes, supporting nutrient cycles, and storing substantial amounts of carbon. Furthermore, the presence of these venerable trees in the urban landscape often represents an integral part of the city's historical narrative. Consequently, researchers and governments in various countries accord special attention to the existence and well-being of these trees as part of their conservation endeavors. However, in Indonesia, there needs to be more research on the characteristics of large and ancient trees in urban settings, particularly concerning their health, biomechanics, and root architecture. Information pertaining to the health, biomechanics, and architecture of tree roots is imperative for anticipating the risk of tree failure and formulating effective conservation strategies. In Indonesia, large and old trees, especially of the dipterocarp species, possess significant ecological and historical value in urban landscapes. A comprehensive study was undertaken to evaluate the variability in the health, biomechanics, and root architecture of large and old dipterocarp trees within the urban landscape of the Bogor Botanic Gardens. Forty-five trees, classified as large (diameter at breast height (Dbh), ≥60 cm) and old (≥100 years), were carefully selected from the ex-situ conservation area. These trees, representing five genera (Anisoptera, Dipterocarpus, Hopea, Shorea, and Vatica), served as the focal point for the study. To assess the health variability of the target trees, the Forest Health Monitoring (FHM) method, developed through a collaborative effort between the International Tropical Timber Organization (ITTO) and the Southeast Asian Regional Center for Tropical Biology (SEAMEO-BIOTROP), was employed. Additionally, the Visual Tree Health Assessment from the International Society of Arboriculture (ISA) was utilized. Subsequent to the health analysis, the biomechanics of the target trees were evaluated using the Euler and Ylinen critical bending height values, along with the safety factor. Concurrently, the root architecture of the trees was examined through the implementation of Object Mapper and Blender software, utilizing ground-penetrating radar (GPR) for detection. The findings revealed a diverse age range among the target trees, spanning from 106 to 156 years. Some of these trees displayed distinctive buttresses, with a mean diameter at breast height (Dbh) of 95.6±50.3 cm, a height (H) averaging 33.9±9.7 m, and a crown diameter (Dc) of 15.9±7.6 m. Notably, tree height exhibited a positive correlation with Dbh and crown diameter. Instances of damage or defects were more prevalent on the lower-upper trunk (35.3%) and within the crown's trunk (29.4%). The primary types of damage identified were a) conk and advanced decay, b) exposed cavity, and c) termite galleries. These damages contributed to a reduction in tree trunk mass density to 84.9±23.5%. Despite these observations, all target trees were classified as experiencing light to healthy damage. Consequently, the risk rating calculation indicated that all target trees held a low failure risk rating (RR). Moreover, a significant correlation was observed between the damage index value (DIV) and RR, with a correlation coefficient of 0.93. The research findings indicate that trees with bigger sizes and buttresses have greater trunk and crown weight loads (123.74 kN, 20,122.19 kN) compared
Keyword: biomechanics, large and old trees, roots architecture, tree health assessment, urban landscape