Contextualizing Tree Defects and Risks in an Urban Tropical Campus, Chulalongkorn University, Thailand

Abstract

Tree failure poses a risk to property and people; however, there is limited data on tropical tree risk assessment, hindering effective risk management. Chulalongkorn University (CU) is an urban tropical forest campus in the heart of Bangkok, Thailand. The campus provides essential cultural, social, and ecological services but is subject to structural failure due to extreme weather and climate change that can cause severe consequences for property and public safety. This study aimed to carry out a tree risk assessment at CU using a form based on that of the International Society of Arboriculture (ISA).  Altogether, 4,255 trees representing 256 species were identified, stressing the need for location of structural defects using adapted risk assessment forms identifying three levels of tree risk urgency management: immediate and critical, urgent, and non-urgent. The most common defects were observed in trunks and bark, branches, and roots. High-risk species included Casuarina equisetifolia, Pterocarpus indicus, and Albizia saman. Introduced tropical tree species demonstrated higher defect rates than native species. These findings emphasized the importance of tree assessments in tropical cities, where management practices and environmental conditions differ from temperate regions. Assessment will contribute to a safer urban public green space, well-planned management, and resilient urban tropical forestry beyond the CU campus and across Southeast Asia.