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Tue April 10, 2012
Hard freeze hurts Michigan cherry crop
by Bob Allen for The Environment Report
A hard freeze has wiped out a big portion of the cherry crop in Northwest Michigan this spring. The area produces more than half the state’s cherries that end up in desserts, juice and as dried fruit.
An historic early warm-up in March left fruit trees vulnerable to frost once the weather turned cooler again.
Temperatures broke records for the month of March across the Great Lakes region.
Climate researchers say there’s never been anything like it going back more than a hundred years.
“We’re seeing history made before our eyes at least in terms of climatology.”
Jeff Andresen is the state’s climatologist and professor of geography at Michigan State.
“And in some ways if we look at where our vegetation is and how advanced it is, it’s probably a month ahead of where it typically is.”
Andresen is careful to point out that this year’s early warm-up is an extreme weather event.
He says it far outpaces the previous warmest March on record in 1945.
He can’t say it’s a direct result of climate change.
But it fits the predicted long term pattern of change that includes extreme fluctuations.
During one period, there were several straight days of above 80 degree daytime highs and nighttime temperatures in the 60's.
At the time, Nikki Rothwell was checking the cherry trees at the Northwest Michigan Horticultural Research Center in Leelanau County.
And she was seeing day-to-day changes in the fruit buds that are highly unusual.
“It’s just been uncanny. When I go out and look at those trees I look at what we saw yesterday in development and then I look at what we saw today in development and it actually looks like it kinda jumped to the next stage of development.”
Normally, that kind of growth would take weeks to occur.
But, Rothwell says, it’s hard to tell what’s normal anymore.
There’s a trend over the last 30 years of earlier spring warm-ups by as much as seven to 10 days, on average.
But the last date for a killing freeze has not moved earlier to keep pace.
Jeff Andresen at Michigan State has done a lot of that research.
With the extremely early warm-up this year, the fruit buds advanced to a stage of development that left them very vulnerable to temperatures below freezing.
And, as Andresen says, it was highly likely that temperatures would return to more springtime norms.
“There has never been a spring season, April, May or June, in which we have not observed freezing temperatures, or actually hard freezes. It’s never happened.”
And sure enough, on the last Sunday night in March, there was a prolonged freeze with strong winds and temperatures in the mid-20's.
It hit the heavy fruit growing areas in Leelanau County particularly hard.
Frances Otto manages Cherry Bay Orchards north of Suttons Bay.
“I’d say we’ve got at least a 90% crop loss.”
The official numbers for the Northwest region are losses of tart cherries in the 50 to 70% range.
Southwestern Michigan and the areas midway up the west coast haven’t been hit as hard.
But there have been more overnight frosts around the time of the full moon that continued to do significant damage to other fruits as well, such as apples, peaches and plums.
And there are other concerns besides a freeze.
Nikki Rothwell of the Horticultural Research Center says growers had to start spraying orchards to kill fungus that was released early because of the warm-up.
“There’s going to be a challenge to fight off more insects, more generations of insects and a longer season of fighting those pathogens.”
And there’s another problem for farmers who still may have a crop.
The fruit blossoms have a short window for pollination.
But now that more normal spring temperatures are back, it’s too cool for honeybees to fly.