The joint conference of the COST Action Urban Tree Guard and EPPO was held in Carcavelos, Portugal, on September 8–10, 2025. It brought together 77 participants from 25 countries to discuss and exchange information on tree biosecurity and related threats. 

The Book of Abstracts provides summaries of the presentations given in four sessions:
I. Surveillance and monitoring – strategies, regulations and experiences
II. Tools and methods in biosecurity
III. Decision support for biosecurity
IV. Communication and awareness in biosecurity