Michigan mast year: Why trees are dropping tons of acorns and other seeds this year

What's with all the acorns falling?

There's a reason homeowners may be finding way more acorns than they normally do this fall. Oak trees are in the middle of a mast year. Here's why:

(FOX 2) - No, you're not crazy. Yes, there are a lot more acorns littering the ground around oak trees this year.

And not just Oak trees, but all sorts of trees are responding to what experts are saying is a mast year.

What is mast seeding?

Normally, trees drop enough seeds to feed the surrounding wildlife.

But every so often, trees produce far more seeds. Seen as a survival strategy by trees looking to reproduce, they'll drop a large crop of seeds every two to five years.

"During a mast year, you're going to have oak trees that are going to produce an over-abundance of acorns," said Luke Brunner, a master arborist with Davey. "They're trying to out-compete wildlife to regenerate themselves."

The natural phenomenon is currently underway in Michigan.

Dig deeper:

It's not entirely clear why, but trees will coordinate with each other — likely through their roots — to drop a large crop of seeds in the same season.

"Trees of the same species can graft their roots together and communicate seasonal needs," Brunner told FOX 2 in a follow-up email. "This year they communicated that it was time to reproduce, which is why so many are producing heavily."

Researchers do know mast years typically follow a warm dry spring, which leads to more successful pollination. This can set up a larger autumn crop.

It also sets up quite the feeding year for squirrels.