I found lots of these ash flower galls today. Despite the devastation by the Emerald Ash Borer, there are ash saplings growing still, some a reasonable size (no doubt they'll be attacked by the ash borer beetle one day). These growths above, look like flowers, hence their common name, but they are galls made by a tiny mite, Aceria fraxiniflora. There is no damage done to the tree, although some find these unaesthetic looking, but I think they are quite intriguing.