Tree health assessment of the heritage tree Eucalyptus alba Reinw. ex. Blume in Bogor Botanic Gardens using visual and tomography technology

Abstract

Eucalyptus alba Reinw. ex Blume is a heritage tree in the Bogor Botanic Gardens, planted in 1892 (130 years old in 2022). Only one specimen in the Garden has a unique trunk shape. Trees that are a match for the heritage category need to be preserved by paying attention to its health condition. The study aimed to analyze tree health conditions based on visual tree assessment (VTA), tomographic technology, and recommendations for its maintenance. The method used is VTA using the International Society of Arboriculture (ISA) and tomographic technology using PiCUS 3 Sonic Tomograph. The results showed that visually E. alba had a low fall/break potential on the main stem. However, using tomographic technology found that decaying on the main stem at various height levels was as follows: 50 cm (95%), 140 cm (76%), 550 cm (18%), and 810 cm (11%). Therefore, E. alba has a high potential to fall on the lower stems because the percentage of decay exceeds 70% with a large diameter (275 cm). Some recommendations are provided, such as maintaining the physiological process of trees by keeping soil fertility, installing termite bait, making a circular fence to the north, periodically decaying measurements (once a year), and providing information boards related to current tree conditions as well as hazard mitigation. Complete or partial logging is not recommended, given the status of E. alba as a heritage tree.