... and this is the same tree last year.
I hope this precipitous decline is temporary, possibly caused by the lack of a really cold winter, but I'd be fooling myself to think a nearly fifty-year-old cherry isn't nearing the end of its life.
Though the flowering cherry is pretty, it isn't appropriate to this place or this garden. The large Sycamore on the right is.
If the decline continues next year, it may be time to cut the cherry down.