COLUMBUS, Ohio — If you live in Ohio and have oak trees on your property, you may have noticed an unusual number of acorns underfoot.

The Ohio Department of Natural Resources Division of Wildlife reported that an average of 40 percent of white oaks and 54 percent of red oaks bore fruit, known as acorns, this year. By way of comparison, in 2022, 39 percent of white oaks and only 37 percent of red oaks produced fruit. Generally, acorn production is highly variable among individual trees, species, and across the landscape, so while some parts of Ohio may see many acorns, other parts may see very few.

Years where trees produce a higher-than-average number of nuts, such as oak trees this year in Ohio, are known as mast years. A single oak tree can produce thousands of acorns during a mast year.

Research ecologist Katie Greenberg from the USDA Forest Service said that it’s actually “a bit of a mystery” why mast years occur. She said that many researchers have conducted studies to understand what makes a mast year and whether it’s possible to predict when a mast year will occur, but it’s been “pretty impossible”. However, she noted that some studies have found connections between mast years and other variables. For example, years with heavy rain or freezes in spring when oak trees are flowering or young acorns are forming could impact the effectiveness of pollination or acorn development, impacting how many trees bear fruit. Even then, the connection between weather and acorn production isn’t strong enough to say for sure.

“One thing that’s a little bit of a myth is that oaks always have ‘boom or bust’ years,” Greenberg said. “There are some really good years and there are also some mast failure years where there are basically no acorns. But there are many, many years when there’s a medium amount of acorns.”

Greenberg pointed out that there are many species of oak tree, including white oak, red oak, scarlet oak, and chestnut oak, that follow the beat of their own drum when it comes to acorn production. Different oak tree species produce acorns at different rates; some years one or two species might produce a lot of acorns, but it’s rare for most species to produce a lot of acorns in the same year.

Mast years are an exciting time for the forest ecosystem. Greenberg called acorns a keystone forest resource because so many animals eat acorns including game species and rodents. Studies have shown that acorn abundance is linked to body condition, winter survival, and reproductive success in acorn-eating animals. Next year, hunters might notice more deer and squirrels since they are more likely to survive the winter and reproduce in the spring.

Acorn production also has a lasting impact on forests’ long-term ecosystem.

“If there’s a high deer population, partly driven because of acorns, their browsing on woody vegetation can actually affect the structure of the forest,” she said. “They might eat specific types of tree seedlings which can impact the forest composition and how successful the survival of young trees will be. This ultimately impacts animals’ habitats.”

Additionally, acorns can help grow a thriving rodent population, becoming food for predators like foxes, bobcats, coyotes, and raptors. Farmers with lots of oaks on their property in Ohio might notice the abundance of wildlife roaming around in the woods, including game species and crop predators. Game species are less likely to feed near agricultural areas and eat crops because they have a wealth of food available to them in the forest. During poor acorn production years, deer and other wildlife must seek alternative food sources.

Looking to do more than just crunch acorns under your feet? You can roast acorns and eat them, although it’s advisable to find a good, credible recipe first. Acorns are high in tannins, which make them very bitter. Roasted acorns can also be turned into acorn flour, if you like to bake. You might also be interested in harvesting a few acorns to plant oak trees of your own. Or, just enjoy the variety of wildlife feeding on acorns and wonder about what the forest will look like next year.