Urban trees are essential for creating healthier, more resilient, and more liveable cities. They cool urban environments, improve air quality, support biodiversity, store carbon, and enhance human well-being. Yet these benefits are increasingly threatened by invasive pests and pathogens, climate change, global trade, and the environmental stresses associated with urbanization.

Urban Tree Biosecurity explores how cities can prevent, detect, and respond to these emerging threats. Bringing together expertise from across Europe, this open access book presents urban tree biosecurity as an integrated framework that connects prevention, surveillance, early detection, rapid response, long-term management, and resilience building. The volume examines the biological and environmental factors that influence urban tree health, the diversity and dynamics of pests and pathogens, and the pathways through which harmful organisms are introduced and spread. It also reviews current and emerging approaches for monitoring and management, including molecular diagnostics, environmental DNA, sensor technologies, remote sensing, decision-support systems, and participatory monitoring.

Beyond technical solutions, the book highlights the importance of governance, policy, communication, and citizen engagement, demonstrating how collaboration among researchers, practitioners, authorities, and communities can strengthen urban forest resilience in an increasingly interconnected world. Combining scientific foundations with practical perspectives, this volume will be an essential resource for researchers, advanced students, urban foresters, arborists, plant health specialists, landscape planners, environmental managers, policymakers, and all those involved in safeguarding the future of urban trees.

Roeland Samson is professor of Urban and Environmental Ecology at the University of Antwerp, Belgium. He specifically investigates the ecophysiological responses of streetscape and park trees to the harsh urban environment, and how these trees can contribute to the liveability of our cities, including ecosystem service provision and their role in nature connectedness of citizens. He also initiated various citizen science project dealing with urban environmental liveability.

Stephen Woodward has over 40 years of international experience in research on tree health issues, mainly focused on the impacts and management of pathogens and the diseases they cause. In addition, he worked on health of urban trees in relation to the wide range of stresses faced in the built environment.

Dr Nick McCarthy is a forestry academic with over 35 years of teaching, research, and leadership at South East Technological University SETU, where he is the Programme Director of the BSc (Hons) in Forestry  and the Director of the Eco-Innovation Research Centre (EIRC). He has held senior international roles, including President of the Institut Européen de la Forêt Cultivée (IEFC) and leader of the European Forest Institute’s Research Network on Planted Forests. His research focuses on forest protection, silviculture, biodiversity, invasive species, and natural bio-pesticides. Beyond academia, he is active in science outreach, biodiversity education, and community initiatives, combining expertise with public engagement.

H. Tuğba Doğmuş Lehtijarvi has 30 years of experience in plant pathology, specialising  in  tree health. Her work has focused on understanding the impacts  of pathogens and associated diseases, and developing strategies for their management in both natural and urban ecosystems.

Johanna Witzell is a Professor of Forest Health at Linnaeus University, Sweden. Her research focuses on forest diseases and tree resistance to pests, pathogens, and abiotic stress. She leads and contributes to national and international projects on tree and forest health, microbial diversity and sustainable forest management. Her editorial experience includes serving as Editor-in-Chief of the Scandinavian Journal of Forest Research and as Section Editor (Pathology) for Current Forestry Reports.