Quantification of Economic Damages and costs of Ash Dieback in France

PI : Anne Stenger (UMR 1136 Interactions Arbres / Micro-organismes – IaM)

Collaboration : M.B. Bogeat-Triboulot et I. Hummel (UMR 1137 Ecologie et Ecophysiologie Forestières – EEF)

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Context — Common ash (Fraxinus excelsior) is an important tree species both from an ecological and economical point of view. In France, Common ash is the fifth most important broadleaved species. At the beginning of 1990s, ash dieback was first observed in Poland and successively in many other parts of Europe. In 2008, ash dieback was reported in North-Eastern France and it is currently spreading through the country. In 2006, the cause of the ash dieback was identified as the invasive species Chalara fraxinea, a fungi originating from Asia. The disease affects both small and large trees and eventually can cause their death. Highly infected trees can be harvested and the healthy portion of the log sold, since not contagious. Although some researches have been started, no effective management protocols are known for controlling C. fraxinea. Ash dieback is a relevant issue nowadays, but the extent of its impact is not yet clarified.

Objectives — The object of this research project is to assess costs and damages generated by C. fraxinea. The damages will comprise not only the degraded timber from mature trees, but also the foregone future incomes from young and mid-age trees killed by the pathogen.

Approaches —We will use the French ash population before the arrival of C. fraxinea as a starting point. We will then simulate its development in time in absence of the pathogen. Successively, we will simulate its introduction, spread, the associated tree mortality and cost of removal of damaged trees. By comparing the two scenarios (with and without pathogen) we will able to compute damages and costs.

Expected results and impacts —The study will quantify the expected damages and costs related to C. fraxinea, its spatial distribution and produce a map with the risk and uncertainty for this invasion for the next 10/20 years