This special issue of Management of Biological Invasions includes an editorial and eight papers from a symposium on “Detection and control of forest invasive alien species in a dynamic world”, held in September, 2019 in Ljubljana, Slovenia.

 The key question addressed during the symposium was how to move towards a better early detection and rapid response system against invasive alien species in forests – also the title of the editorial led by the symposium organizers from the Slovenian Forestry Institute and Zavod Symbiosis.

 Novel insights from three symposium workshops are combined in a paper about the main challenges and solutions in early detection and rapid response (EDRR) systems using four model species: American pokeweed, grey squirrel, the emerald ash borer, and Geosmithia morbida (causal agent of the thousand canker disease).

 Two papers focus on new methods for the detection of invasive alien species in forests: aerial photos and satellite images to automatically detect Japanese knotweed (Fallopia japonica) and a multiple-lure traps to detect a wide variety of longhorn beetles (Coleoptera, Cerambycidae).

 Alarmingly, one study found that the distribution and host range of an infectious disease of pine trees in protected areas in Italy is much larger than previously reported, having important management implications.

 A discussion of two citizen science projects (Observatree and LIFE ARTEMIS) shows that investments in awareness-raising and species recognition can pay off and improve tree health monitoring systems.

 Volunteer groups can also be helpful in the detection of invasive mammal species, as shown by this overview of grey squirrel management techniques in Europe.

 Involving citizen scientists in monitoring requires an awareness of possible ethical questions and dilemmas, as explained by Michael Pocock and others.

 It also requires an understanding of society at large as shown by this study on attitudes towards invasive alien plants and management of waste disposal in urban forests, which is an important

pathway for the introduction of invasive plants.

 Please visit our website and download Volume 11 Issue 4 of Management of Biological Invasions – it's Open Access!