On a cool, early spring morning in March, Liz Griffith stands among her apple trees, reaching to the very highest branches with a pole saw. Birds that have already returned north call to each other over the “snip snip” of shears, as Griffith and her staff prune through eight acres of apple trees on her orchard in Cottage Grove.
Griffith and her team aim to complete all the pruning before “bud break,” when the first bits of growth of the season’s apple crop emerge from the tips of the branches. This year, Door Creek Orchard staff are racing against the weather.
“It’s a beautiful day,” Griffith said halfheartedly. “Trying to enjoy it.”
Warm winter weather makes Griffith and other Wisconsin fruit growers nervous. Consistent mild temperatures in February and March mean apple trees bloom earlier, extending the window of time those blooms could be damaged when the temperature inevitably drops again.
Wisconsin fruit growers have always had to manage spring frost, which can damage the fruit or kill the crop entirely. But this year is particularly worrisome — and experts believe it’s a sign of challenges to come.
Temperatures recorded by the National Oceanic and Atmospheric Administration for February 2024 were the warmest on record for Wisconsin. Climate change affects weather patterns in the Upper Midwest and the crops that grow here. Warmer and erratic winters can mean a smaller harvest, or freeze-damaged (though still edible) apples. Climate change presents a variety of variables for apple growers, threatening the long term viability of the Upper Midwest fruit industry.
Because most of Wisconsin’s apple crop is consumed within the state as juice, cider, sauce and pie, that means consumers will see the effects in a few months too.
Now, in late March, Griffith’s apple trees have woken up from their winter dormancy and are on track to bloom ahead of schedule. Growers are worried.
“I'm always concerned,” Griffith said. “I am more concerned this year.”
The new winter
According to Wisconsin state climatologist Steve Varvus, the meteorological winter happens December through February. This year, that season was the warmest it has ever been for eight states in the U.S.
Wisconsin — along with its Midwestern neighbors of Minnesota, Iowa and Missouri — had the warmest February on record, according to the National Oceanic and Atmospheric Administration (NOAA).
During the last 25 years, Wisconsin’s winters have been warmer than they have been historically, Varvus said. Meteorologists began tracking statewide temperatures in the 1890s.
“I would bet every single winter from now on is going to be warmer than the long-term average,” Varvus said.
This year’s mild winter is partially attributed to El Niño, the cycle of warming tropical Pacific Ocean waters that distorts global jet stream patterns keeping cold arctic air from circulating as widely.
This year both the months of December and February made records for higher temperatures in Wisconsin. The latter’s average was 31.8 degrees Fahrenheit. But Varvus said that doesn’t necessarily mean the state will coast into spring.
“We are not out of the woods by any stretch. We could still get more cold. We could still get more snow,” he said.
In late February, most of Wisconsin saw temperatures in the high 60s and low 70s, only to experience a drastic drop to 15 degrees Fahrenheit overnight. For the first weeks of March temperatures were mild, only to return to a period of days in the 20s and 30s. These swings between warm and chill temperatures are to be expected, said Varvus, what’s colloquially called “false spring.”
These are the types of swings that apple growers worry about.
“That's one of the ironies of a warming climate,” Varvus said. “It's easy to think, well, we'll have longer growing seasons, that'll be great for growers, but it's not necessarily the case.”
The trees need to sleep
Wisconsin fruit trees and vines benefit from a cold winter. When the weather cools in the autumn trees become dormant — they essentially go to sleep. The longer the trees are asleep the more “cold hardy” they become, enabling them to withstand subfreezing temperatures.
“The colder it is during the winter, the more cold hardy they're going to get and the more heat they're going to need in the spring to be able to wake up,” said Amaya Atucha, a fruit crop specialist with University of Wisconsin Extension.
Aside from one week in January, this winter didn’t get very cold, so the trees aren’t as cold hardy. Early warming pushes the trees to start growing fruit earlier and faster, said Atucha. A spring frost can occur anytime the temperatures drop below freezing.
The earliest part of the growing process is when the fruit begins to emerge from their buds, which keeps them protected in cold weather. It's like taking off a winter coat.
“At this point, they're a lot more sensitive to cold damage,” she said.
Atucha is also an associate professor in the Department of Plant and Agroecosystem Sciences at University of Wisconsin - Madison. Her family owns an avocado orchard in Chile where she grew up. Atucha worked with peach and apple growers in Colorado before coming to Wisconsin.
Now her research analyzes how fruit crops respond to changes in the environment. Atucha said that traditionally, apples were very cold hardy in the middle of winter and didn't break bud as early as other fruit crops, which was perfect for Wisconsin.
But with warmer winters, that might be changing.
“Climate change is really affecting fruit production in our region because of the frequency of the spring frost (and) the risk of having more spring frost,” Atucha said.
If it becomes riskier to grow apples and other fruits in the Upper Midwest due to weather, it could threaten the viability of the industry here. But Atucha is hopeful and is in regular contact with Wisconsin apple growers about how to protect their orchards.
“We have the capacity, especially in a place like UW-Madison, (to) do so much research, to be able to find solutions and alternatives for the growers,” Atucha said.
‘Are we going to get a crop or not?’
Deirdre Birmingham remembers how warm it was in March of 2012. Over half of the month saw temperatures above 60 degrees.
“That just set trees in motion,” she said.
For 21 years Birmingham has run The Cider Farm with her husband John Biondi in Mineral Point, located in the Driftless region west of Madison. Their orchard spans 18 acres and grows 16,000 trees that produce apples for hard ciders and apple brandy, sold retail and served at their west side Madison cidery.
Weeks of warm weather in 2012 caused Birmingham’s trees to bloom. When temperatures dropped overnight that spring, frost killed 80% of their crop. They were able to harvest only around 100 bushels of apples, resulting in a very limited release of apple brandy from that year.
Apples are perennials, so the “wacko weather,” as Birmingham calls it, can affect trees for years. The following season, 2013, The Cider Farm trees rebounded and actually overproduced.
“Then we had 1,000 bushels. We went from 100 to 1,000 … I was grabbing everything I could possibly put an apple into to hold apples,” she said.
Early bud break and spring freezes are among the many variables apple growers have to navigate. Cold winter temperatures are also beneficial for killing off pests and reducing the risk of disease.
“Growers at this time of the year, you're just like, are we going to get a crop or not?” said Birmingham.
Due to the risk to her orchard, Birmingham finds herself cheering for what most would consider terrible weather each spring.
“(In) 2022 we had just an ugly, slow, cool, dreary spring,” she said. “Being an apple grower, I was like — well, it's not so nice out. But, boy, it reduces my anxiety level.”
Fighting the freeze
Given the perennial issue that spring frost poses, growers have come up with a few mitigation strategies. Some larger operations turn huge fans on their trees to circulate air, bringing warmer air down to the orchard floor to protect the trees. A few others use sprinklers to coat the trees in a layer of ice — water releases heat energy as it freezes.
At Door Creek Orchard, Griffith applies a micronutrient treatment to her trees before and after a frost. She also mows the orchard floor short so it can absorb more sun energy during the day and release it at night when it's cold. And when the temperature is predicted to drop extremely low, Griffith stokes bonfires throughout the orchard overnight.
“The jury’s out on whether that really does anything because the heat is so diffused, but let me tell you it makes you feel better,” Griffith said. “While it's happening you are doing something, you are burning wood and … not just lying in bed staring at the ceiling, mourning the loss of your crop.”
These mitigation strategies to fight the freeze require the right conditions to work, said Steve Louis, board member with the Wisconsin Apple Growers Association.
Frost fans, the giant blades that bring warmer air down in attempts to heat the orchard, are expensive. And when it's cold enough there simply isn’t any warmth to be had.
“They’re not a silver bullet,” said Louis.
Louis grew up on his family’s orchard in Richland Center. He now manages the 180-acre Oakwood Fruit Farm, growing 25 different varieties of apples. The farm has been in business for 120 years. Louis said he’s noticed winters become warmer in the last two decades.
Nutrient treatments need to be applied 36-48 hours before a freeze for there to be enough time for the trees to benefit. That’s hard to accomplish when there are multiple days of freezing temperatures.
“At some point, it just stacks up so much that you can't overcome it,” Louis said.
Spring frost can occur late in the season. In 2021 there was a freeze on May 30.
“Normally we have to get through April and May,” Louis said. “Now we have to get through March.”
Wisconsin has 1,208 apple farms, according to the 2022 USDA Agriculture Census. Apple trees are a long term investment, Louis said. When orchards lose a crop due to spring frost, the amount of work and expense to care for the trees remains relatively the same, whether there was a profit or not.
“We can't just abandon the orchard for the year,” he said.
“If you have something that comes in and ruins a crop of corn or a crop of beans or any annual thing, you can start over the next year,” Louis said. “We don't have that luxury.”
Can apples adapt?
Climate change is evolving Wisconsin’s agriculture environment. Last year the United States Department of Agriculture updated its Plant Hardiness Zone Map, a tool growers use to determine what perennial plants and crops will grow best in which regions depending on climate. Wisconsin’s planting zones were adjusted with the new maps, most significantly in the northeastern part of the state. The Madison area went from 5a to 5b, representing a 5-degree average difference.
Researchers are studying a number of genetic traits in fruit crops that could be bred to create varieties that are less likely to lose cold hardiness as quickly, said Amaya Atucha, the UW-Extension fruit crop specialist. Scientists are also exploring traits that would delay bud break, increase drought resilience and reduce heat stress.
“It's kind of like a very special apple tree that we want,” Atucha said, one with fruit that tastes good.
Apples growers adjust their orchards over time through grafting, the process where plant tissues are combined to grow together creating a new variety of apples or a tree with different characteristics like cold hardiness or drought resilience. Still, breeding new fruit varieties and grafting existing trees to adapt to new climate conditions can take years.
“You cannot easily adjust what you're growing,” Griffith said, if you already have trees in the ground.”
Door Creek Orchard grows 90 different varieties of apples on eight acres near Madison. The most popular are Cortland and Honeycrisp. Although different varieties bloom at different times, it’s only usually a period of 10 days to two weeks, not enough for any of them to avoid the risk of a spring freeze entirely.
“All the varieties are going to be more susceptible to spring frost if we tend to have warmer winters and warmer springs,” Atucha said.
‘Embrace ugly fruit’
Wisconsinites consume the majority of Wisconsin’s apple crop. Local orchards sell their apples to customers through farmers markets. Some host pick-your-own directly from the orchard.
Louis encourages apple lovers to visit their local orchards and buy produce from farmers markets.
“Try and support your local farmers every chance you get,” said Louis.
If a spring frost happens when the fruit trees are still budding, the apple is likely to survive but it may be misshapen or have skin damage called frost rings.
“Some people are not going to want to eat that apple because it looks weird, right?” said Griffith with Door Creek Orchard.
Given that this year’s winter weather increases the risk of a spring frost, growers are trying to prepare the public for an earlier, or shorter, apple season. Quantities may be limited if there is crop loss from a freeze, Griffith said. Apple lovers should expect some apples to look different.
“They'll have to be really ready to embrace ugly fruit,” said Griffith.
Atucha said that fruit producers are sometimes hesitant to talk about the challenges they are facing during the growing season, thinking it’ll keep people away during harvest. Losing an entire crop due to a spring frost can happen, but it's relatively rare. It's more likely that the season will be slightly shorter and selections will change.
“If you want to support your growers, call them and show up, because there will be apples.”
Source - https://captimes.com
