How would the trees know, I wondered?
Turns out the trees don't know, and that abundant acorn production is actually a natural cycle of 3-5 years. These years of banner production are called 'mast years'. Mast is the fruit of nut-producing trees, specifically a kind of piling up on the ground for animals to eat. A 'mast year' is a year like the one we're having in the southern US where we have an overabundance of nuts (a massive understatement at my house). The cycle goes like this: there will be a year or so of piles of acorns on the ground (mast comes from the Old English word maest, literally meaning piles of tree fruit and nuts on the ground), squirrels and other animals feed on the nuts. Then come the years with less production, and what's on the trees is what gets eaten--not a lot left over to fall to the ground, and the population of nut-eaters thins because of scarcity of food. Then we have a year with large production, there are more than can be eaten by the current population of nut-eaters and you have our result. Pileups of nuts like the ones in the pictures below.
So now when you hear parents on the sidelines of your child's soccer match complaining about the massive amount of acorns on their decks, you have one more little tidbit of useless, but interesting, knowledge to share over your morning coffee.
