Ash die back?

One of the small ash trees below the viewpoint on the Knott appears to have succumbed to ash die back disease. The crown is dead and there is just a small amount of new regrowth low on the trunk, it's just hanging on. The more I look for signs of the disease the more I see.  It's difficult to know what this means for the Knott, will there be a lost generation of ash trees as the mature trees all die?  Or will some survive, albeit like this tree with a very reduced growth form?  The ash is prolific in its seed set and there are literally millions of seedlings  waiting for a canopy gap to stretch up to the light. It's known that a small percentage of individuals are resistant to the disease, and that could mean that in a generation's time there will be plenty of mature resistant trees on the Knott.

On other matters, with Gus unwell in the morning after his tummy troubles, so instead of the morning walk I took the bike out early to investigate the source of the booming bittern.  Deep in the reedbeds it was booming away, a bass backdrop to the chorus of reed and sedge warblers chugging and chattering, and the explosive song of cetti's warblers. A glorious start to the day.

Gus was more settled by the time this was taken at sunset, though I still needed to get up with him at 2 am on Friday for a walk to the woods.  As I write this later on Friday morning, he is settled and was fine on his morning walk. Hopefully, that's the last of that episode.