Ask Mr. WeatherBlogger
Larry Triplett, of Pasadena writes: "I wondered if the near total lack of acorns this past Fall was in any way a weather event?"
An astute observation, Larry. In fact, Mike Galvin and his colleagues at the Urban and Community Forest Program (Maryland Department of Natural Resources) were talking about just that very question recently. "Your reader has a keen eye," he told me. "It's something we experienced all over the state."
Every fall, he said, the forestry folks spread out across Maryland to gather up seeds dropped by a variety of native shade trees, including oaks, ash and black walnut. They're sent to the state nursery in Preston, in Caroline County on the Eastern Shore. There, they're planted and cultivated to produce seedlings for reforestation work.
But last fall there was a notable scarcity of acorns. White oaks, northern and southern red oaks - none of them had produced much of a crop. And it has certainly put a crimp in the diets of the state's deer and squirrels and bears. It also forced the forestry folks to seek acorns from out-of-state suppliers in order to get enough seeds for the state nursery.
Weather can affect acorn crops. A severe and prolonged drought, I'm told, can prompt some oaks to produce especially heavy loads of acorns, apparently an adaptation designed to assure that the species survives, even if the individual tree dies from a lack of water.
This time, however, weather probably did not play a role, Galvin said. All else being equal, oaks produce acorn crops in cycles. Depending on the variety, they tend to drop bumper crops every two, three or five years, with scant production in the "off" years.
Last fall appears to have seen a coincidental convergence of "off" years for all oak varieties in Maryland. "There was a dearth of acorns across the state, of different oaks," Galvin said. There was no weather event that caused it, he said, and "there wasn't any significant oak mortality or disease around."
The good news is we're all likely to be swimming in acorns next fall. Maybe that will keep the deer out of the garden.