Tree Risk Evaluation in the Multifunctional Public Space of Vastenburg Fort, Surakarta City

Department of Environmental Science, Faculty of Mathematics and Natural Sciences, Universitas Sebelas Maret, Surakarta, Indonesia 57126

^* Corresponding author: sapta.suhardono@staff.uns.ac.id

Abstract

Tree falls can cause ecosystem disservices and pose threats to public safety, particularly during the rainy season in Surakarta City. Government records noted 113 fallen trees from 2023 to March 2024. This study examined tree-related risks in the Vastenburg Fort area, a multifunctional public space often used for various activities. The assessment followed the Tree Risk Assessment guidelines of the International Society of Arboriculture (ISA), emphasizing the likelihood of failure, target vulnerability, and potential damage. A bottom-up inventory was conducted to document tree species and individuals within the site. The survey identified 31 species, with a total of 354 trees dominated by shade-providing varieties. Based on the likelihood of failure analysis, most trees (63.56%) were in stable condition with low failure risk, though 4.52% were classified as critical due to visible structural damage. The likelihood of impact analysis showed vulnerability, with 14.41% of trees having high potential impact and 32.49% categorized as moderate. The cumulative risk assessment suggested that, overall, the tree population was in relatively good condition. Low-risk trees made up the majority (93.5%), indicating that although tree falls remain a concern, proactive monitoring can help maintain safety and ecosystem balance.