What is on the Ash tree?
What you are seeing are ash flower galls. It is a mite that feeds on the flowers (what you are seeing is from last year) and causes the galls. Here is a link to a factsheet with some additional information - http://www.entomology.umn.edu/cues/Web/065AshFlowerGallMite.pdfAre you currently treating your ash tree to protect it from the emerald ash borer? Please let me know if you have additional questions or concerns.