Now that the rains have started, the grass has started growing again.
“I feel like I need a helmet and flak jacket out here,” Nature Boy said recently as he wheeled the lawnmower out of storage.
A breeze rattled through a looming Garry oak, and another dozen of the year’s acorns pummelled down around us.
One pelted Nature Boy on the shoulder. As he flinched, another ricocheted off the driveway and winged past his nose.
“My case in point,” he said, ducking back into the garage. He rummaged around and emerged well-padded in a puffy jacket, a pith helmet on his noggin, and safety Âgoggles on his nose. “This should do the trick.”
The previous night, neither of us had slept well. It wasn’t the racket of rushing wind, sheeting rain or gushing gutters that had kept us awake.
It was the nighttime nutfall.
The Garry oak trees around our house had been playing conkers in the dark, Âbombarding the roof, walkways, yard, fence and even windows with their acorn bounty. The shelling involved only the cracking of acorn shells, but some of the salvo had sounded like pistol cracks and cracking Ârooftiles and window panes.
The region’s Garry oaks have produced larger numbers of nuts this year. The acorns seem, on average, bigger than usual too. Many of those scattered intact around the yard measure an inch or more in diameter, compared to the one- or two-centimetre nut jobs I’ve saved from past years.
Already, Nature Boy has shovelled up two garbage cans full of the nuts.
Like many trees, oaks have cycles of boom and bust. Boom years are called “mast years” and occur every two to five years. In these years, an oak tree can produce as many as 10,000 acorns, or up to 20 times its average output.
Producing the excess ensures that acorns will remain after critters have finished Âfeeding on them.
Seeds are high-octane packets of energy. Every seed contains enough stored starch and protein to power the initial development of the first nutrient-questing root and first stem and leaves of the potential tree within the seed.
The high-carb, high-protein energy kick makes acorns an autumn-food-of-choice for many critters, including squirrels, mice, rats, chipmunks, Steller’s jays, deer and even bears. And acorn abundance feeds an increase in rodent populations in the Âfollowing months. This, in turn, leads to increases in rodent-eating hawks and owls.
For trees like oaks that depend on having their seeds carried away from the parent tree and buried by squirrels and jays, a mast year yields an extra benefit. When there are lots of nuts to go around, the critters bury more of them, seeding oaks across the Âlandscape. The animals may forget some of those caches, leaving baby oaks to sprout over the following months.
The specifics of why and when mast years happen remain unknown, but some Âweather-related inputs can help with Âprediction, however. Pollination of oak flowers is primarily wind-driven, but insects also play a role. A spring freeze may kill the flowers, and heavy spring rains may dampen pollination, yielding smaller acorn yields. In such years, bumper crops are unlikely.
Some oak species don’t handle spring and summer drought well, but Garry oaks are adapted to this region’s wet-dry seasonal extremes. If anything, they’ll likely opt to drop limbs in response to long dry spells rather than curtail the chance to reproduce. Other oak species not native to the area may not have fared so well this year.
Next fall, however, we’ll probably see (and hear and feel) fewer acorns fall. ÂProducing seeds takes a lot of energy out of a plant, and a big batch of acorns in one year usually means Garry oaks will Âconcentrate on making new leaves and wood and Âreplenishing stored starches for a year or three or four before producing another high yield.
That means that next year’s bumper crop of squirrels will have to find other food sources to sustain itself or face its own Âpopulation crash.
And next year’s nutfalls will be less of a bruising, denting, dinging bombardment. Helmets and flak or puffy jackets won’t be required.
