Squirrels or nature? What’s responsible for acorn deluge in Oakland yard?

DEAR JOAN: Is this a banner year for acorns?

I’ve lived in this house for over 40 years and don’t remember this many acorns. I hear them raining on my roof and deck in the night, loud enough to disturb sleep. Are squirrels active at night and causing the falling of acorns?

I’m also seeing deer that are quite young — no spots, but seem too young for this time of year. Is this normal?

Helen, Oakland

DEAR HELEN: It’s a good year for acorns, but not a banner one, which in tree terms is called a mast year.

Scientists judge mast years on the past, and for an acorn crop to meet the mast standard, it needs to be a certain percentage over the biggest productions. So far, that’s not the case in 2022.

Acorn production is a fascinating topic. The myth is that a lot of acorns foretells of a cold, wet winter, but acorns are all about the past, not the future. Whether an oak tree puts out a lot of acorns in a season depends on how many acorns it grew last year and the weather that year, and most importantly, whether we had a warm, dry April.

Scientists aren’t exactly certain why April weather is so important, but they surmise that because an oak tree can’t fertilize itself, dry April winds help spread the pollen that does the work. They also believe that the oak trees need time to recover from acorn production, so a big crop one year usually means a smaller crop next year.

They also know that the oak trees tend to synchronize themselves, so that if one species of oak trees produces a large crop, the other trees from that species will, too. As unsettling as it might be to think about trees communicating with each other, they do. And what’s more, they plot against the squirrels and birds that eat the acorns. When the animal populations grow robust, the trees might become stingy with their crop, forcing the animals to move elsewhere in search of food or to limit the number of offspring they have.

Once the animal populations have declined, the trees will go crazy with the acorns, which means more of the seeds will end up in the soil, growing new oaks, rather than in the bellies of squirrels and woodpeckers. It’s about survival.

But to answer your question, your oak tree is doing what comes naturally to it — producing acorns and dropping them to grow baby oaks. The cooler temperatures signal the trees to disperse their crops, and the squirrels are tucked in their beds at night, not out shaking the limbs. You can bet they and the other critters are quite happy to see what the tree left them in the morning.