One of our Shrub Oaks fell over this year. The remaining trees are dropping an abnormally large number of acorns.
The acorns are larger than normal and well formed. Perhaps they miss their friend. Or it could be that the wasps that lived in the bark of the dying trees were destroyed when I cut the tree down. The wasps lay the eggs in the acorns.
The acorns start off bright green on the tree then turn a dark brown before falling. Acorn shells make great mulch.