Ask ELi: What’s with All the Acorns?

Photo by Jim Pivarnik.

Editor’s Note: After reading our last “Ask ELi” column, in which local forester Mike Vasievich answered a question about buck rubs, a reader wrote in to ask, “Can you ask Mike why we have so many acorns?” We did, and here’s his answer.

Why might your oak tree have so many acorns this year?

Some oak trees produce bumper crops of acorns (or other seeds or nuts) in some years, and in other years, the acorns are scant. A lot depends on the species of tree.

The size of the crop depends on the growing conditions the previous year and also what happens when the tree flowered in the spring. Oaks have separate male and female flowers on the same tree but acorn production doesn't really depend much on the abundance of male flowers. That's because growing each acorn requires one female flower.

Nut crops on trees are called “mast” (not a very common usage of the noun). For most oak species, really heavy mast years occur every three to five years. That can vary by tree or location.

For some species of oak, like bur oak or sawtooth oak (an introduced species), the nut crop is fairly consistent and high from year to year.

Deer like eating acorns and other nuts like beechnuts. People who want to encourage deer in their woodlands often plant these species of oaks to have a steady annual supply of acorns.

Want to try planting an oak tree from an acorn? Many of the acorns you find on the ground or even up in the tree are duds. They are usually infested with a small insect, a nut borer larvae of a beetle, which drills a small hole into the acorn and eats out the inside to grow.

If you want to collect acorns to grow, pull the caps off and put them in a bucket of water. The ones that float will not grow. Scrape those off and discard them. Most of the sinkers are potentially viable, but even some of them may have worms.

Plant acorns in the fall soon after collection or else keep them in some moist sand in your refrigerator and plant them in the spring.

Be aware that squirrels are pretty good at sniffing out buried acorns and may dig them up for a snack.

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