Biodiversity lexicon: A for ash tree mortality

Sick trees on the other side of the fairways; trees that have been cut down and are waiting to be removed. This is becoming increasingly common in Europe. Ash tree mortality in particular, is also causing problems for golf course operators. This is a tree disease that has been observed in Europe since the early 1990s and now affects large parts of the continent. The disease is caused by a fungus called Hymenoscyphus fraxineus, which was introduced from East Asia. While Asian ash species are mainly resistant to the fungus, ash trees native to Europe are often very susceptible.

The fungus spreads via spores that can be carried for miles by the wind. These spores mainly infect young shoots and leaves, leading to symptoms of wilting, dying branches, and bark necrosis. Young trees, in particular, often die completely, while older trees are weakened over a longer period of time and are more susceptible to further diseases or pests. In addition, the stability of severely damaged ash trees can be compromised, making them a risk on golf courses, as they can endanger players as well as walkers.