Zones, they are a changin’
Warming trend saps sugaring season, worries fruit growers
REGION – Long, bitter winters used to be the norm in northern Michigan. But this year, and in year's past, significant stretches of cold temperatures have become such an anomaly in northern Michigan that the U.S. Department of Agriculture has altered something it hasn't touched before: It's changed the region's rating on its hardiness zone map.
A veritable bible for gardeners and growers, the USDA zone map defines the climate conditions of areas in which a specific category of plant life is capable of growing – essentially the lowest temperatures plants can withstand. The bulk of northern Michigan has long been a 5a (minus 20 degrees Fahrenheit); now – and going forward – it's a 6a (minus 10 F).
Sound a little anti-climactic? It's not, said Dr. Jeff Andresen, state climatologist for the Michigan Department of Geography: "We're six to eight degrees warmer on average – that's a major change."
According to data collected over the past 30 years, the warming is occurring mostly during the winter months, and spring in northern Michigan is occurring seven to 10 days earlier than it did 30 years ago.
This winter, he said, is tied for the third warmest on record.
The temperature differential is a growing concern for fruit growers in northern Michigan who are seeing an influx of pests, such as flea beetles, previously foreign to the area.
"A pest that overwinters in the top few inches of soil, if cold, is killed," Andresen said. "However, in warmer temps, the insect survives … the flea beetle is a major vector for plant fungal diseases."
Andy Norman, plant science and viticulture program coordinator for Michigan State University through the University Center, said farmers and landscapers in the region and across the state need to pay close attention. "Zone 6 increased remarkably along the Michigan shoreline. We lost 3b and the 3a zone entirely in Michigan," he said. "Our colds are getting warmer."
Fruit trees aren't the only ones stressed. Northern Michigan's evergreens and its distinctive American white birch, now in the wrong climate zone for their needs, are at risk, Norman said.
Greg Kindig, a farmer and maple syrup producer in Benzie County, told the TCBN that this sugaring season "is ending close to when it usually starts." Kindig reported that in some areas, sap started running in December.
The change meant boiling more sap to get syrup, "maybe as much as 60 gallons of sap to get a gallon of syrup, versus 32 or 40," according to Kindig.
Lawrence Brink, a forester in Grand Traverse County, said the recent storm that blanketed the area in heavy, wet snow, downing trees and knocking out power to thousands of Michigan residents, is the least of his worries. Protecting trees that are beginning to bud out is now a priority.
Duke Elsner, with MSU Extension in Grand Traverse County, said fruit growers have little defense against frost damage: "It does not take extremely cold weather to injure buds once development has begun; temperatures in the 20s would be all it would take." He added, "Fruit growers have virtually no defense or response to the threat of freezing injuries their crops are facing."
Cherry Farmer Sandy Rennie of Williamsburg agrees. He said precautions like smudge pots and wind generators can help, but resources are limited.
"If it's a choice between survival and not, you go to protecting your best producing blocks," said Rennie.
Rennie said the normal bloom time for cherries occurs between May 10-12 on average, but he's seeing that change. "We have all of April to get through; we're dealing some real issues here." The second-generation cherry farmer told the TCBN a shift by a week might be significant. "Now, we're two to three weeks off. This weather is scary – you don't know what you're dealing with."
While frost is a major concern, Rennie said an early season is just as bad: "Even if you survive the frost, the people aren't here to buy the fruit." And that means a drop in the price of cherries.
Rennie said the proximity of local cherries to the bays have helped in the past, but lately, the big water isn't freezing, meaning warmer air coming up from the water.
Enjoying all that open water, however, are Canada Geese. The geese didn't bother leaving Michigan at all this winter – which is increasingly typical, said Anne Hobbs of Cornell University's Lab of Ornithology.
And American Robins were being sighted as early as mid-February in northern Michigan. Cathy Litwaitis-Kruse saw her first robin in Central Lake in February. "I always get excited to see my first robin of the season," she said. "But I've never seen a robin in February." BN