Cranberries Can't Hide From Climate Change

By SARAH SCHUMANN/ecoRI News contributor

Stephen Ashley is a third-generation cranberry grower. (Sarah Schumann/ecoRI News)

Stephen Ashley is a third-generation cranberry grower. (Sarah Schumann/ecoRI News)

TIVERTON, R.I. and FREETOWN, Mass. — Crimson in color and tart on the tongue, cranberries add both sustenance and symbolism to the Thanksgiving table. As with turkey, pumpkin and other hallmarks of America’s feast day, their historical significance stems from their role in fortifying early New Englanders against the harsh winters once common in this region. But although cranberries remain a Thanksgiving staple, the cold winters that gave rise to this custom are fast becoming a thing of yesteryear.

As warmer winters and less predictable weather patterns become the norm, local cranberry growers are beginning to analyze what climate change means for this classic New England industry.

“It’s changed a lot in thirty years,” said Stephen Ashley, a third-generation cranberry grower and owner of 18 acres of bogs at Puddingstone Farms in Freetown. “You’re irrigating a lot more. You’re frost-protecting a lot more. Now it’s harder, because the weather changes so much now.”

Since cranberries must be cultivated under a specific set of growing conditions, they may be particularly sensitive to the effects of climate change. Native to the lowlands of the region’s glacier-pockmarked landscape, cranberry plants thrive in acid peat soils and require an abundant supply of fresh water and sand.

But most importantly, Ashley said, they require a pronounced and consistent seasonal pattern. “That’s why you can’t grow cranberries around the world. They need winter, spring, summer and fall,” he said.

Last winter’s warm temperatures raised questions about whether cranberry vines, which are perennial, experienced their requisite dormant period. According to extension worker Frank Caruso of the University of Massachusetts Cranberry Station, warm temperatures forced cranberry growers to cut short the usual winter treatment of flooding bogs with water in order to protect vines from wind and frost.

Then last March many growers were taken by surprise when record-breaking 80-degree temperatures plummeted to the 20s. Cranberry vines that had started to bud ahead of schedule were suddenly at risk of freezing, and growers rushed to flood their bogs with water to prevent the abrupt change in weather from ruining a season’s crop.

“In my thirty years, I hadn’t experienced that. I didn’t know how to deal with it,” Ashley said.

Cranberry cultivation requires constant vigilance. Not only must growers intermittently flood their bogs during cool months to protect vines from freezing temperatures and strong winds; in summer, they must irrigate their bogs to protect berries from scalding. This summer’s seven-week drought meant that many growers had to spend more time and money on irrigating their bogs, Caruso said. Some growers have been digging their pond holes deeper in recent years, according to Ashley, to compensate for the increased need for irrigation water.

The warm temperatures that lingered into the fall this year also meant a delay in the cranberry ripening process. Cranberries don’t begin to ripen until nights become cool, and growers, who are paid according to the ripeness of their berries, put off the harvest as long as possible. The result was a compressed harvest season, which can mean higher expenses for growers.

“This year was altogether different,” said Lucien Lebreux, owner of 12 acres of bogs at Middle Acres Farm in Tiverton.

The lack of ice during recent winters also has meant a pause to the traditional practice of ice-sanding bogs. Cranberry vines require a fresh coat of sand every three to five years to maintain healthy roots and promote stem growth. Typically, growers apply sand by driving sand-spreading machines over their frozen bogs. This practice requires a solid sheet of ice, and because of warming winters, it has now been six years since many local growers have been able to ice-sand.

“No ice. We haven’t sanded in I don’t know how long,” Lebreux said. “We’re going to have to drive on the vines, or use a boat to sand.” In contrast, he added, “When I was a kid, you used to go skating on the swamps at Thanksgiving.”

Warmer winter temperatures also are implicated in a growing incidence of insect pests. Populations of the winter moth, which eats the buds and flowers of the cranberry plants, have been on the rise during the past 15 years. No longer subject to a winter die-off, winter moths are now able to survive year-round.

More frequent storms resulting from higher sea-surface temperatures may pose an additional risk to cranberry farms. Last summer, hale storms damaged cranberry vines, causing some growers to lose as much as half of their crop, Ashley said. This fall, Hurricane Sandy flooded several seaside bogs with salt water, causing chemical stress to the vines, according to Caruso.

“The thing about a cranberry grower is that the weather is your boss,” said Ashley, who checks the weather forecast several times a day. “You work for Mother Nature. I watch all of the weather channels, and I plan my work around that.”

Although they are sensitive to weather extremes, cranberries may be better poised than some other crops to adjust to the effects of climate change. “They’re more capable of coping, because they’re a native plant to this area,” Caruso said. “That helps them adapt.”

Despite changes in the weather, some things remain the same. One of those is cranberry growers’ dedication to maintaining their livelihoods and passing down their traditions to future generations.

“It sure beats working in some sweatshop somewhere,” said Ashley, who is teaching his young grandsons to tend the bogs. “It gets into you, because you’re outside, you’re in the rain, you’re in the snow. It’s in your blood.”