Good Fruit Grower / February-1st 1996 / Freezes are becoming a distant memory

 Email  Print

Freezes are becoming a distant memory

It's been a generation since Washington State's fruit districts suffered a major freeze, an uncommonly long period of time.

In the old days, orchardists could expect a destructive freeze at least every 4 to 14 years. And that's not just a figment of fading memories.

Bill Luce, former Washington State University Cooperative Extension agent in Yakima, wrote in his publication The Washington State Fruit Industry... A Brief History that the first records of tree damage were following a freeze in 1908-09, when the fruit industry was in its infancy. A freeze in the winter of 1919-20 hit the whole state, and a cold wave in September 1926, was one of the earliest freezes ever recorded.

Other destructive freezes came in 1935, 1948-49, 1955, 1964, and 1968-69. Since then, there have been only relatively mild freezes that have not caused damage of the magnitude seen periodically before.

"In the last 20 years, we've had much longer stretches of time between any kind of orchard freeze," said.Dick Bartram, retired WSU Cooperative Extension agent in Wenatchee, who has written papers on the state's freezes.

Retired meteorologist and consultant Jim Holcomb of Wenatchee said.he cannot speculate why there has been such a long period without a serious freeze.

"It might be just a cycle we're in, where we could go back into that cycle again," he said. "We hit cycles like this that last many years.

"Maybe global warming is a real thing, and that might be a cause of it," he added, "but I would hesitate to put my name on a claim like that."

There are many who still recall the great freeze of 1955. The cold hit early. Temperatures plunged close to 0°F on November 11. The weather just before that had been unusually warm, and most trees still had their foliage.

Tom Van Well, sales manager at Van Well Nursery, remembers temperatures in the 60s before the freeze. "It just killed nursery stock. I think we probably lost almost 90% of our nursery stock because we had just started digging trees and we weren't in any hurry. The freeze froze them in, and it killed a lot of them."

It was a similar story at C&O Nursery, Wenatchee. Tests on sample trees at the Tree Fruit Experiment Station in Wenatchee indicated they were not extensively damaged, former company president John Snyder recalled. However, most of the 600,000 trees the nursery supplied to growers that year failed to grow, and the company had to provide replacements the following season.

"We feel if we ever again had a freeze like that, we would not even attempt to save the crop," Snyder said.

The freeze also affected orchards. Many trees had been recently planted in central Washington, and about 25% of the trees were under ten years of age in 1955, according to Bartram. About half a million young apple trees were killed. Pears suffered much less damage than apples, but cherries were also severely damaged.

"It was a very rapid drop in temperature," said.Dr. Del Ketchie, horticulturist at Washington State University in Wenatchee. "It really caught our young trees--that were still vigorously growing--off guard."

Trunk and crotch injury was the major form of damage, but there was also injury to terminal growth, which made it difficult to find scion wood for bridge grafting work.

Van Well said.there has been speculation that the reason the freeze affected trees particularly in the five to seven age group is that they were just coming into production, and because they were carrying fairly heavy crops, they went into the winter under some stress.

The Walla Walla area of Washington and neighboring Milton-Freewater area in northern Oregon suffered the worst cold in 1955. Temperatures in early November were as low as -15°F, and the loss of fruit trees, particularly stone fruit trees, was devastating.

Tom Waliser, an orchardist in the area, estimates that 98% of the trees in the Milton-Freewater area where he grew up were killed in that freeze. The whole valley was replanted, and a tomato industry developed, as people turned to other crops for income until their new trees came into production.

The 1955 freeze, and the one in 1964 that followed it, both caused the greatest damage to young trees. The cold weather came in the late fall or early winter.

But the 1968-69 freeze, which came at the end of December, affected mainly trees over 20 years old, and was confined to north central Washington.

Wally and Shirley Loudon had bought an old 45-acre orchard in Carlton, in the Methow Valley, in 1964. Minimum temperatures in nearby Twisp set new records in December 1968.

"We saw 47 below on our porch, and we didn't look again," recalls Shirley. "I would hear these bangs and I blamed it on the house expanding or contracting, or whatever, from the cold, but it was the trees exploding. It was the bark bursting, and you could hear it. That's how wild it was."

In 1968, the Loudons had picked a crop of 20,000 boxes. In 1969, the season after the freeze, Wally went out and picked a crop of 700 boxes single-handed. He got a job as a field representative with Northwest Wholesale in Omak to make ends meet and farmed at weekends for a few years. The freeze killed about half the trees. The previous spring, he had planted 5,000 new trees as interplants. Although they survived, they did not thrive.

"The orchard was never the same again after that," Wally said.

He replanted most of the orchard but decided to stay with Northwest Wholesale and sold the farm about six years later.

Loudon points out that although potential tree loss would be more devastating in high density orchards today, because of the sheer number of trees, it would take growers less time to come back into production than it did in 1955 or 1968.

"It took them ten years to get back in business," he said. In the meantime, they might have to find work elsewhere or raise different crops.

Snyder said.the losses in the 1968 freeze led to considerable replanting industrywide. "At that time, we were getting into the newer strains and varieties. Although it was a loss to the growers, it actually in disguise was somewhat of a blessing that they went into the newer strains, particularly in the Red Delicious."

Ketchie agrees that the freeze had a silver lining. "It took out some of the Richard Reds and it got people leaning more toward dense plantings. It moved things in a better direction, even though the individuals really suffered financially."

He said.many orchards were taken out, and production in the Methow Valley decreased. Controlled atmosphere storage had recently been introduced, and Methow Valley growers, who were able to grow fruit that stored well in regular storage, found they no longer had that competitive advantage. "They just couldn't hack it economically after the 1968-69 freeze," Ketchie said.

Van Well said.after the 1955 and 1968 freezes, growers would ask nurseries to grow trees on winter hardy stock, such as Hiburnal or Antonovka. "We would always do that for three or four years after the freeze, and then people got away from it again."

Holcomb, the meteorologist, said.the particular combination of cold air mass and circulation pattern to cause a major freeze, though rare, is likely to recur sooner or later.

"It's probably inevitable that it's going to come along again," he said.

But when it does, the circumstances will be different from 1968, when Winesap was still a popular variety, the Columbia Basin's potential as a prime apple growing region had yet to be recognized, and the state's total apple crop had not yet reached 30 million boxes.

"It would have a severe impact if they had another one like that, because for one thing there's quite a few more trees in more vulnerable areas, and they're different varieties." Holcomb said. "There are a lot more orchards out in the Columbia Basin than there were in 1955, and those could be affected by wind chill. It's a windier area."

Experience during the 1968 freeze shows that wind can worsen tree damage, because it has the effect of lowering the temperature. And many of the newer orchards, particularly in the Columbia Basin, have been planted on sandy soils, exposing them to potential root damage during cold temperatures.

The lack of a major freeze means the cold hardiness of the rootstocks most commonly used in high density orchards, such as Malling 9 or M.26, has never been fully tested, Bartram points out.

Ketchie said.there is some question whether more hardy rootstocks, had they been available, would have been any advantage during the 1955 or 1969 freezes, because most of the damage affected the tops of the trees. In 1968, there was plenty of snow cover, and some orchards were almost buried.

However, they would have helped during the winter of 1990-91 freeze, when there was less overall tree damage reported, but more root damage than ever before, particularly in sandy soils. Temperatures of -18 to -25°F were recorded at the end of December in central Washington orchards.

"That was the biggest root injury we ever had," Ketchie said. "Not only did we not have any snow cover, but there was no moisture in the soil. We were in really bad shape then."

The Russian rootstock Budagovsky is reputed to be more winter hardy than the widely planted Malling 9 rootstock, but Ketchie said.his tests have shown otherwise. However, the Polish series, including P.22 and P.2, does appear to be hardy.

Karen Maib, Washington State University Cooperative Extension horticulturist in the Columbia Basin, said.even though there has been no severe freeze, winter injury is generally the number one cause of tree loss in the Columbia Basin.

"I think we're still looking for hardy rootstocks, but maybe we're not looking hard enough because we don't feel the threat there all the time. When the freeze comes--and it's going to come--for the next few years, we'll be looking for hardy rootstocks, and then we'll forget."

Maib said.Columbia Basin growers should count their blessings for every year that passes without a major freeze because the area's light soils leave the trees vulnerable to damage. And major tree losses in the Columbia Basin would have a significant impact on the state's production, as the area produces about a quarter of Washington's crop.

"There are a lot of unknowns, but it's inevitable that some year we're going to get hit bad, and, hopefully, people are prepared for that and they have money in the bank. That's all you can do, other than you select rootstocks for winter hardiness, and you probably wouldn't have any money in the bank anyway."

She said.some growers have used Budagovsky 9 rootstock, but winter hardiness is not the primary reason for selecting the rootstock.

"Our freezes are so sporadic, I don't know if you can go to the bank with that," she added. "Do I give up precocity for hardiness? Do I give up rootstock effects for color development for winter hardiness? Probably not. Is winter hardiness part of my formula? Absolutely.

"Winter hardiness has to be a factor in the selection of rootstock and variety over here in the Basin."

Should a freeze like the one in 1955 hit the Columbia Basin in early November, some growers would be caught with their Fuji crops still on the trees.

But Ketchie said.Fuji appears to be one of the most winter hardy varieties around. He said.there is a misapprehension that the later a variety matures, the less winter hardy it is. "It's the hardiest commercial variety we grow right now," he said.

However, Braeburn is sensitive to cold damage, because it does not go into a deep dormancy, and it deacclimates quickly if the weather turns warm during the winter. "Braeburn is vulnerable most of the winter, especially if you have some warm climate just before," he said.

Snyder said.the last freeze was so long ago that there's a tendency for younger growers to not be concerned about the hardiness of their trees.

He said.growers could take the precaution of hardening their trees off in the fall by cutting back on water, but then dry soil leaves the trees open to root damage if there is no snow cover. Either way, it's a gamble.

"If we had one like the 1955 freeze, there would be a lot of growers I'm afraid would never be able to come out of it," Snyder said. "Fortunately, fruit growers are born optimists, or they wouldn't be in the business."