FARGO - Did you notice the heavy crop of seeds on the region's trees this summer and fall? Elm seeds fell by the millions this summer at our home in Fargo. People around the region shared photographs of buckets filled with acorns and walnuts as trees produced bumper crops of seeds and nuts.
Folklore says when trees produce an overabundance of seed, it forecasts a cold, snowy winter.
Is this true, or is it an old wives' tale?
Where gardening's concerned, I'm never quick to dismiss old wives' tales because some of the best gardeners I've known have been old wives. And plenty of old husbands are also passing along this weather-predicting folklore involving tree seeds.
The phenomenon of trees producing oodles of seed, and also seeming to synchronize this between unrelated tree species in a large geographic area, is a well-known and well-studied habit of trees called "masting," from the Old English word for nuts accumulating on the ground. Years when trees produce overabundance of seed are called "mast years."
Scientists admit that all is not yet known about the phenomenon. How does an oak in Bismarck, N.D., coordinate with an elm in Fargo, which passes the word to a maple in Park Rapids, Minn., that it's time to reproduce with a bumper crop of seed? It's almost as though there's communication between trees. Did Mother Nature tell them a bad winter is approaching?
Here's the scoop on trees' weather-predicting ability. Because mast years have been widely studied worldwide for centuries, there's plenty of data to analyze. There is no historical correlation between a heavy seed set in trees and a bad winter. Masting of trees is not necessarily followed by a severe winter, and if it is, it's coincidence, as heavy seeding has also been followed by mild winters.
WDAY-TV's chief meteorologist John Wheeler says, "There are many folk myths about predicting winter weather involving squirrels, muskrats, caterpillars, etc. None of them have any scientific credibility because they are all purely anecdotal and simply do not hold up to empirical testing."
North Dakota State University Extension Forester Joe Zeleznik adds, "Some people think that a heavy seed crop is a harbinger of doom. If a tree 'knows' it's going to die, it'll put all of its energy into one last burst of reproduction. I know of no data to support that."
Foresters at Minnesota's Department of Natural Resources and the University of Minnesota's Extension Service agree that trees aren't weather forecasters, and this year's masting doesn't foretell a severe winter.
So, if trees aren't preparing for a bad winter with a heavy seed set, why did they synchronize it?
Even countries as distant as Germany are experiencing the mast year of 2018. Although much is yet to learn, scientists know that in mast years, trees are responding to past or present conditions, not the future weather. Past or present temperature, moisture, food reserves or pollen production, coupled with possible chemical or hormonal signals between trees, are responsible.
Scientists are analyzing all the mechanisms that trigger a mast year, but what's the reason trees do this?
On a cycle of two to seven years, trees likely produce an abundance of seed for the preservation of the species. Squirrels, birds and chipmunks can't possibly consume the huge quantity of seed or nuts, leaving enough extra to sprout into baby trees, ensuring future generations.
A wise move on the part of trees.