ORAL PRESENTATION: Genetic management of European ash (Fraxinus excelsior) forests in the face of ash dieback through enrichment plantings

Submitted by : Fady Bruno
Abstract type : Oral presentation
Session type : Conference session 4: EVOLUTIONARY MANAGEMENT of FORESTS
Author Speaker : Devrim Semizer-Cuming

Information about other authors :

Lene Rostgaard Nielsen, Igor Jerzy Chybicki, Reiner Finkeldey, Erik Dahl Kjær

Abstract :

The emerging infectious pathogen Hymenoscyphus fraxineus has been decimating common ash (Fraxinus excelsior) populations throughout Europe for more than two decades. This causes socio-economic losses and ecological problems as well as concerns over the future existence of the species in European forest ecosystems. Previous studies have reported heritable genetic variation in ash dieback susceptibility, suggesting that ash may possess genetic potential to recover in the long run via natural selection. Enrichment plantings with tolerant trees based on the offspring from selected and tested ash trees can support the recovery process by maintaining the species in the forest and allowing them to disperse their seeds and pollen. However, the efficiency of such a strategy will depend on the reproductive fitness of surviving trees and the extent of gene flow between planted and old trees. We therefore investigated seed and pollen dispersal at two different sites, Rösenbeck (Germany) and Valby Hegn (Denmark). We further tested the hypothesis that healthy tolerant trees have higher reproductive success than trees with high disease susceptibility in the populations severely affected by ash dieback. Here we used health assessments combined with microsatellite data from a clonal trial at Tuse Næs (Denmark) and the mixed continuous forest of Valby Hegn. We found that ash trees had spread seeds and pollen several hundred meters into the surrounding, managed forests. We also found that healthy trees had superior reproductive success. Our results suggest that natural recovery can be supported by enrichment planting of seedlings propagated from tolerant ash genotypes. Human intervention may therefore prove valuable to ensure the future existence of ash in European forests when sound genetic principles are integrated into management practices.  

Bibliografic references :

Keywords : ash dieback, enrichment planting, Fraxinus excelsior, seed and pollen dispersal
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