There are about a billion acorns all over the ground this fall and people keep asking me what it means. I had always heard that a huge number of acorns presages a cold winter, a winter that arrives late and is bone achingly cold, but honestly neither I, nor most scientists that study these things, really know what triggers these overabundances.
There are lots of trees that have years of overabundance, and in Europe, where people have kept notes on the fruiting patterns of many species of trees for hundreds of years (because that’s what Europeans do) there’s been no real rhythm or rhyme in environmental clues as to why trees in some years have such a large number of fruit or nuts.
What we do know is that when oaks do this, they are having what is a called a mast year. The phrase comes from the word masticate, and it refers to any fruit, seeds or nuts that any trees or shrubs produce which could be considered food for animals. A mast year is when a fruiting tree produces 5 to 10 times as many seeds, or fruits or nuts than it normally does. Although these bumper crops are cyclical, the cycles don’t seem to be regular. My apples do this, some years we have crazy heavy crops and the next many of the trees are much lighter, but not all of my varieties of apples do this, so I always have a lot of apples, but not always on all my trees. And it’s not as simple as the heaviest fruiters taking a break the next year. This year I have three trees that aren’t really producing any apples, but none of them are the tree that had the most apples. The tree that made the most apples last year, so many that branches the size of my thigh in diameter snapped and dropped under the weight, was again this year, just plain overwhelmed with apples.
But back to our masting acorn trees. According to some scientists, the phenomenon might be weather related, and since acorns take one to two years to form and fall (depending on the species), it would be the temperature and precipitation (or lack of it) from the previous year that determined the rate of acorn production from year to year. Unfortunately, it’s not can’t be quite that simple, since masting trees tend to happen simultaneously across a geographic area so large that the weather patterns within it are too diverse to be the only cause.
Some believe this widespread synchronization is caused by a chemical signal or cue the trees are giving off that triggers them to have such abundance. Another thought is that masting trees are just the results of trees that are have succeeded in maximizing the efficiency of their pollen. If all the oaks everywhere can release their pollen simultaneously, they will have a seriously improved their chances of germination and thus increased acorn production.
Every year oak trees drop acorns, acorns they’ve produced to guarantee they have offspring. These offspring are the way to ensure the future of the oak population, so each year every oak tree should try to produce more acorns than they need to, just to make up for those that the various squirrels, turkeys, chipmunks, voles, deer and mice (the masticators) are going to eat up over the winter. And this is the basis of the last theory on masting trees.
In a regular year a single oak tree will produce thousands of acorns, but in a mast year it can produce up to 10,000 acorns. This strange occasional cycling of massive amounts of produce and then a dearth (boom and bust) means that the acorn predators are kept off balance. If a tree produced the same amount of seeds or apples or nuts every year, the predators of those seeds, apples and nuts would have a reliable food source and would just keep growing in population until there were enough of them that the would gobble up every single thing these trees dropped, and there would be no chance for the trees to have offspring. Have a few years when there are not a lot of acorns (a series of bust years) and the population that’s been dining on their nuts will starve and crash. Then, if you can follow a bust year with a boom year or two, and the predator population has crashed, some of your boom year acorns will have a significantly better chance to sprout and become seedling oaks. Evolution will of course favor those trees that reproduce the best, and the ones that do it by tricking their predator population with mast years seem to be leading the way.
There are two additional side effects things to a mast year of which we need to be mindful. First that when there’s plenty of food for the voles and squirrels and mice, the following year there will be plenty of food for the predators of these small mammals, the raptors. This is great news, and I’m super excited that this abundance of acorns means that the owl and hawk populations are going to explode. Unfortunately one of the top acorn eaters in our area is the white-footed mouse, and when there’s an explosion of acorns, the following year there’s normally an explosion of these mice, the same mice that are really more responsible for the deer tick population in our neck of the woods than the deer they are named after.
So more acorns also means more mice which means mores ticks which means more Lyme disease. Sigh. Thanks acorns.
On a side note, when I tried to explain the cycling of the acorns to my husband Dereyk, he asked why if all these other mammals ate acorns, humans didn’t and I proudly got to tell him that acorns are actually a great source of protein, fat, carbohydrates, potassium, vitamin C, magnesium, calcium, phosphorus and niacin and that the Iberian ham made from pigs fed on a diet consisting mostly of acorns is thought to taste as good as it does because the high level of anti-oxidants in the acorns prevents lipid oxidation in the ham. And of course I added that I had, in fact, once eaten dotorimuk, a thick Jell-O like substance made from acorns when I was dining in a monk run vegetarian restaurant in Seoul, but that I wouldn’t make acorns a staple in our food pantry, since most species contained high levels of tannins that make them awfully astringent and bitter to the palette. And that acorns were once considered a staple food substance for Native Americans and that the ancient Greeks partook of them as well.
Dereyk just shook his head at me and said that right there was a perfect description of the kinds of people we were. That I was a person who ate acorns and he was a person that only ate things that ate acorns. And that he thought he was on the better team, but that next time I had the acorn Jell-O I should ask them to make it with a lot more sugar.
Paige Patterson is STILL picking up apples from all over her yard.