Published: 2008-10-29 07:56:38
Updated: 2008-10-29 07:56:38
Posted October 29, 2008
By Ruth Ann Grimes
MIKE MOSS SAYS: Ruth, I'm not a horticultural expert, but based on some papers I've scanned and discussions with some extension agents who are, oak trees are known to produce acorns on a cycle that varies some among species, but generally involves one to four years of lean production followed by a "bumper crop." Efforts to tie this cyclical behavior to weather conditions preceding or following the heavy years have produced mixed results, so it's unlikely that fall acorn production is a meaningful winter forecast tool.
That's not to say that acorn production isn't influenced by the weather experienced by the trees leading up to fall, just to note that correlations between various weather elements and the production levels are in many cases rather poor. Given that, it's hard to see how the trees' behavior would be a good indicator of future weather conditions. One could even make a case that if the trees "sensed" a bad winter coming, they might conserve energy and resources, and save the abundant acorns for some time when conditions are more favorable for them to germinate easily and early the following spring.
While no one can be absolutely certain, one explanation for the cyclical abundance of acorns that has gained some favor is that it is an evolutionary adaptation that helps to make sure some acorns survive to germination every few years. The idea is that if acorns were very numerous, and equally so, year after year there would soon be a very large and steady population of animal species (squirrels, chipmunks, deer, etc) that consume them, and that nearly every acorn would be eaten soon after it is produced. If the trees go a couple of years with very light production, however, so that those populations are thinned out somewhat, then a sudden burst of large quantities of acorns will outstrip the appetites of the animals in the area, so that some acorns will "survive" and new trees can grow.
The only official long-range seasonal forecast for winter doesn't offer a lot of specific information to go on, as the Climate Prediction Center currently expects a slight tendency for below normal precipitation and above normal temperatures for North Carolina.