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Showers Of Acorns Tapering Off!


My forecast contains more showers of acorns in the next couple of weeks. They will be scattered across the region where any oak trees are located. The showers have been frequent and, periodically, hard-hitting even nearly warranting the wearing of helmets! Thankfully, the intensity is decreasing now as much of the crop has plunged to the ground.

Acorns are scorned by homeowners like me. When my wife and I purchased our home about 30 years ago, the only issue that we overlooked was the presence of numerous oak trees on the property and neighboring land. Over the years, I have removed several of these trees but the remaining ones continue to cause consternation and much work in some autumns. Oak trees have irregular cycles of boom and bust. The boom times are called "mast years" when just one huge oak can drop up to 10,000 acorns! I am convinced that we have probably raked up enough acorns to fill a dump truck with 8-10 cubic yards(slight exaggeration) of these so-called seeds! It is the second consecutive mast year and these acorns are driving me nuts! If your yard is governed by oak trees, I am sure you are dealing with the same dilemma.

Oak trees remain a mystery to researchers partly because they exhibit strange synchronized behavior. Perhaps because of a mix of genetics and climate, oaks are able to turn acorn production off and on in nearly perfect rhythm with no scientific predictability except that it appears to be cyclical in a 2-7 year range. Prior to last fall, there were 4 consecutive years yielding few acorns. It is theorized that controlling factors are external environmental or weather-related and internal physiological or energy-related. Each species of oak responds to a certain set of weather conditions that triggers an expense of energy for the production of seeds.

Today's Trivia On WBZ News This Morning:

Q: Which one has the greatest impact on acorn production?

a) a cold, wet spring

b) a warm, wet summer

c) a dry, windy fall

d) a mild, snowy winter

A: a) a cold, wet spring

Year-to-year acorn production is much more unpredictable than the weather mainly due to external factors and the genetic-makeup of that particular oak family. Freezing weather during the flowering period can kill the flowers resulting in small crops. Acorn production can also be limited by insects, nutrition, humidity and soil moisture plus high wind and excessive rainfall which affects pollen distribution to male flowers. Oak trees often abort acorns during periods of stress thereby conserving resources such as water and nutrients. We saw that transpire during this drought year as acorns started dropping very early.

It is thought that a cold, wet spring would produce leaner crops while a warm, dry regime during the flowering period encourages greater pollination and bigger crops especially in those favorable cyclical years. Yet, bumper-crop years aren't always weather-blessed and poor years occur even when the weather conditions seem ideal.  The trigger of a mast year is further complicated by the fact that acorns of some species are formed in a two-year cycle suggesting that weather conditions two years prior to the fall crop have an impact. Dr. Marc Abrams, a professor of forestry at Penn State, says there is a chemical signal hypothesis meaning that the oaks are giving off some sort of signal that cues them to have an abundance of acorns. Masting is an adaptive reproductive strategy according to the speculation of ecologists. Their predator satiation idea states that oaks starve would-be seed predators in the lean years and overwhelm them in the bumper years. In both cases, enough seeds are provided for the regeneration of trees.


According to Mass Audubon, mast years have ecological consequences for years to come. With more acorns come more predators like squirrels, chipmunks, mice, turkeys, deer and even bears. More deer and mice would likely mean more ticks and the higher risk of contracting Lyme disease not to mention the annoying loud constant chirping of chipmunks!

In conclusion, despite a range of explanations proposed by scientists ranging from environmental triggers to pollen availability to chemical signaling, the irregularity of mast years remains an enigma. One thing is quite clear. A mast year is NOT a predictor of a severe winter. Winter predictions are based primarily on complex atmospheric/oceanic linkages. The WBZ AccuWeather Team will deliver its 2016-17 winter outlook next month.

Meantime, if you're unlucky enough to have oaks in your yard, I wish you HAPPY RAKING!

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