What Deer Eat: Understand the Hard Mast Puzzle

We can predict the arrival of the rut nearly to the day. We can forecast the specific path of a ferocious storm. We can predict with some accuracy how many people will get sick in this year's flu season.

So why can't we predict America's acorn crop from year to year, or even from ridge to ridge? The answer is important to anyone who hangs a stand in an oak tree, because the production of hard mast--mainly acorns, but also beech and hickory nuts--can make or break a deer season across our hardwoods belt.

Acorns deserve our attention as a crucial piece of a whitetail hunter's forage puzzle, even though the little cones of fat and protein sometimes get more credit--and blame--than they deserve.

In good mast years, hunters in the right place can expect plenty of deer crunching on acorns, which must seem to deer like manna from heaven. But good acorn years can also reduce deer's reliance on food plots, redistributing bucks away from managed forage.

In poor acorn years, food plots become much more important, but the unknowable variable is how many deer gravitate away from your property in search of acorns elsewhere.

Given the importance of hard mast, you would think that biologists, deer managers, and keen-eyed hunters would have a handle on acorn production. But it turns out that even cultivated nut trees are maddeningly inconsistent mast producers, and wild trees have additional variables that affect acorn production.

Grant Woods, a biologist and land-management consultant, equates acorn-crop predictions with the weather. "I consider weather predictions accurate enough to schedule activities from about three days out," says Woods. "I consider acorn predictions from a month out. There are simply too many variables to predict production out further than that."

▶ Variables include:

• Late and early frosts can kill the flowers that mature into acorns.
• Abnormally cold weather can kill overwintering acorns.
• Dry summers can atrophy flowers, especially on white oaks.
• Wind and hail can destroy acorns any time from flowering to before ripening and drop.
• Insects can damage up to 80 percent of the acorn crop some years.

Even in a normal year, when those meteorological variables are tempered, acorn production can be spotty, says Blake Hamilton, a horticulturist at Mossy Oak's Nativ Nurseries in West Point, Mississippi. "Folks often forget that fruit-producing trees are dependent on pollinators," says Hamilton, who oversees a nationwide network of acorn collectors who contribute seeds to the nursery. "A productive oak tree is a product of a healthy landscape." By that he means a biodiverse landscape, one with plenty of wildflowers that attract bees, butterflies, and other pollinators. He recommends either planting or hunting in an area with a wide variety of vegetation that flowers all season, ensuring that pollinators are in the neighborhood when the oaks flower.

But Hamilton also says hunters can predict with some degree of accuracy the relative productivity of an oak tree from one year to another.

"Some trees are just more consistent producers than others," he says. "It's a function of good soil, genetics, adequate moisture, and minimal competition. When we are looking for source trees for our seed stock, we're looking for those oaks that produce acorns in drought years as well as in cool, wet years."

Hunters can do the same thing when they're scouting treestand locations. A tree that produces a consistent acorn crop every year is ultimately more valuable than one that drops a bumper crop of nuts only once every three or four years.