Native ash trees (Fraxinus excelsior) are severely affected in their distribution and development by the fungus Hymenoscyphus fraxineus. The pathogen responsible for ash dieback is widespread across ash stands in Bavaria. Since its first detection in Germany (2007) and Bavaria (2008), the disease has progressed rapidly, with high mortality rates across all age classes.
In 2009, 24 monitoring plots were established throughout Bavaria, where annual assessments of infection and tree vitality were conducted. By 2024, the surveys concluded - only seven plots could still be evaluated, as the ash population on the remaining sites had completely died out.
The data were analyzed with respect to several questions: the temporal dynamics of dieback, mortality rates in relation to diameter at breast height, tree height, and site type (lowland, riparian, and montane forests). Following a descriptive analysis and data quality check, discrete-time survival models were applied.
Contact at StaBLab: Johannes Piller
Project partner: Dr. Nicole Burgdorf, Bavarian State Institute of Forestry