Rising temperatures across Europe, extreme weather events, higher fire risk, or increased vulnerability to biotic disturbances such as pests and diseases are some of the consequences of climate change on forests. In the case of biotic outbreaks, scientists have been investigating how to make tree populations more resilient from a genetic perspective and to understand alternatives for tree conservation in case of diseases or pests.
To further explore this issue and understand the scientific advances, the European Forest Genetic Resource Programme (EUFORGEN) Secretariat organised in February a webinar series entitled “Biotic outbreak management of the Genetic Conservation Units Network: case study on ash dieback”, which consisted of three online sessions open to the public.
The sessions held by EUFORGEN featured a panel of researchers and scientific experts to examine the specific problem of ash dieback in Europe from different angles, with an average of more than 180 virtual participants.
Webinar #1 – 3 February 2023
The first online session focused on the spread and invasion of diseases and pests affecting ash tree populations. In the case of ash dieback, since the mid-1990s this disease has spread widely in Europe and has caused the death of more than 90% of all ash trees in several countries.
The guest speakers for Webinar #1 were Michelle Cleary, forest pathologist, and Rimvydas Vasaitis, researcher and a field mycologist, both from the Swedish University of Agricultural Sciences (SLU). The two webinar talks focused on the aspects of ash dieback disease spread as well as the emerging invasion of emerald ash borer in these tree populations.
Webinar #2 – 10 February 2023
Given the spread of ash dieback throughout Europe, what can be done? Is the common ash species doomed to disappear? The second webinar dealt with genetic tolerance and resistance to ash dieback. During the session, some studies were presented which conclude that some trees seem to be able to limit the spread of infections through partial resistance mechanisms. These results offer some good news for the common ash as a species, meaning that it is unlikely to become extinct.
The guest speakers for Webinar #2 were Richard Buggs, Professor of Evolutionary Genomics at Queen Mary University of London; Ben Bubner, Head of the Unit Pathogen Resistance Research at Thuenen Institute of Forest Genetic; and Heino Konrad, Head of the Unit for Ecological Genetics, Department of Forest Biodiversity and Nature Conservation, at the Austrian Research Centre for Forests (BFW).
Webinar #3 – 17 February 2023
Most trees, including ash, exhibit high genetic variation within populations, which increases the likelihood that ash trees surviving diseases will continue their evolutionary processes after undergoing natural selection such as ash dieback. These “resistant” trees are very valuable for reintroduction, reforestation, and genetic conservation as they have great adaptive potential.
The third and final online session of the series explored this topic and addressed natural selection in ash populations in relation to the spread of ash dieback and its genomic evidence in an unmanaged forest. The guest speakers for webinar 3 were Erik Dahl Kjaer, Professor of woody plant genetics at the University of Copenhagen, and Richard Buggs, Professor of evolutionary genomics at Queen Mary University of London.