Why are so many acorns on the ground in Chicago? It's a 'mast year

The abundance in acorns this fall is the result of a phenomenon that happens once every few years, in which oak trees produce far more acorns than normal.

Tons of acorns? It must be a mast year

Tons of acorns? It must be a mast year

Are Your Trees Dropping Acorns Like Crazy because winter will be tough? - Farmers' Almanac - Plan Your Day. Grow Your Life.

Why Are More Acorns Falling? Excessive Drops of Nuts from Oak Trees Is Part of Normal 'Mast Year' Phenomenon

TIL Certain oak tree populations will synchronize to produce almost no acorns, only to rain them down excessively the following year, known as a mast year. The year preceding the mast year

Whole lot of nuts: Mast year or not, there are lots of acorns on the ground this fall, Westerly

The Acorn Harvest

Why your oak tree is producing more acorns

So many acorns on the ground -- it's a mast year for oak trees. - The Washington Post