For a few weeks each spring, the cherry orchards of California’s San Joaquin Valley burst into a sea of pink blossoms. It’s a beautiful sight and a sign that the harvest will be good. But in recent years, farmers have noticed a change in this pattern, and it signals drastic changes ahead for the state’s cherry farmers.
Reporter Mark Schapiro: I’m heading to the San Joaquin Valley, capital of California cherries. Cherries are part of the lore here, and not just the lore: They’re a $200 million-a-year business.
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Under the right conditions, cherry orchards like this one can produce nearly 3 tons of juicy cherries per acre. But scientists and growers have noticed that the odds of having a good crop seem to be changing. Jeff Colombini’s family has been farming cherries for three generations.
Jeff Colombini (president of Lodi Farming): Biting into a fresh cherry – there’s no experience like that on earth, in my opinion.
Reporter: But Colombini is worried.
Colombini: If you look over here, you can see a situation where the lower part of the tree – you’ve got leaves that are out already, you’ve blooms that are done blooming. …
Reporter: This spring, instead of coming in all at once, the blossoms are coming in stages or not at all.
Colombini: ...You’ve got flowers that are just opening and at the very top leaves that are just starting to come out. I mean, it’s just a very sporadic bloom.
Reporter: Sporadic blooming is a classic sign that a cherry crop is in trouble. Cherries need to hibernate – below 45 degrees over a sustained period of time. Farmers call that chilling hours.
Colombini: When a cherry tree doesn’t receive enough chilling, it's a, it's a big problem for the, for the production of cherries, because what happens is the buds become, when they break dormancy, the flower buds become imperfect. They’re missing parts. So when you don't have the perfect flower, you don't have an ability to form a cherry.
David Lobell (assistant professor of environmental earth system science, Stanford University): What we’ve seen over time, over the last 30 years, is those chill hours that accumulate in the winter have been getting smaller and smaller over time – which means that the successful growth of these crops is becoming more and more challenging.
Reporter: Lobell’s research has predicted that California’s cherry crop could decline by as much as 20 percent by 2050.
Perennial crops, like trees and vines, produce some of the state’s most valuable foods, nearly one-third of California’s total agricultural value. But they’re also particularly vulnerable to climate change.
Lobell: Typically, they’re in the ground for 20 or 30 years. And what that means is – unlike a crop like corn, which you can change out each year – you’re really committing over a long period of time where the climate is likely to be changing. And so you have to make much more of a long-term decision, and you have to start to think about climate change maybe more than you would if you had an annual crop.
Reporter: At the Delta Packing Company, this year’s cherries are being cleaned, sorted and packaged for markets around the world. A box like this can go for as much as $125 overseas.
Matt Nowak (account manager, Delta Packing): We're seeing probably two-thirds of a reduction in volume that we would normally see out of our southern growing regions. Right now we're, we're running one 10-hour shift a day in the early part of the season. Typically this time, as we're getting started, we're running two 10-hour shifts, and there's a lot more volume coming through.
We obviously don't have as many people working in the area right now, which is impacting families. If the cherry crop is, is not producing, really all around, it's gonna have a pretty bad effect on the industry as a whole.
Reporter: Cherries, it turns out, are the canary in the climate coal mine. They’re highly sensitive to changes in temperature and rainfall, which scientists say are being altered by climate change.
And in 2012, there’s an added twist to the story: Data from weather stations like this one show that while the trees did seem to receive enough chill, a lack of fog may have caused the buds to overheat.
Dennis Baldocchi is a biometeorologist at UC Berkeley.
Dennis Baldocchi: What we’re trying to do now is look at long-term climate records and new data sets from satellites to see if there’s a trend in reduced fog. The idea is that if it’s warmer, there’s less chance for the air to condensate and form fog – so more sunlight on the plants, more sunlight on the ground, and the sunlight hitting the buds of the trees will make them much warmer than the air temperature, and so again, the plant will experience less winter chill.
Reporter: While the 2012 cherry crop rebounded late in the season, farmers have been seeing the risks of unpredictable weather. In 1999, the U.S. Department of Agriculture offered crop insurance for cherries for the first time. Records show that farmers bought more policies to cover more liabilities almost every year since.
Lobell: There’s always going to be good and bad years in agriculture; even in the future, there will be some good years. But those will become relatively less common, and what we now consider a bad year will become relatively more common. It’s a gradual changing of the odds of having a good year versus a bad year.
Reporter: And who paid for the estimated $22 million in California cherry losses last year? We did. Taxpayers paid for over a third of that and will likely do so again in 2012, according to the USDA.
California cherry growers have traditionally had a competitive advantage in the U.S. market.
Joe Grant (farm adviser, UC Davis): The earliest cherries grown in the United States come out of California because our climate is warmer than Oregon, Washington, Michigan, New York – the other places cherries are grown. The market price for sweet cherries very early in the season is very, very high. And we're marketing cherries into that window, when there's virtually no other competition from other cherry-producing areas.
Reporter: But now, Grant says, California’s moderate climate may be getting too warm, and cherries could become unsustainable. Breeders are trying to forestall that day with varieties that need less chilling, but it’s been slow going.
Zaiger’s Genetics is a forerunner in devising new varieties to adapt to California’s changing climate. Biologist Floyd Zaiger is famous for creating the pluot, a cross between a plum and an apricot. As a young man, he started working on a low-chill cherry.
Leith Gardner (General Manager, Zaiger’s Genetics): Fifty years ago, he brought in an early-blooming cherry. I believe it came from Spain, 'cause that's a little before my time, and we just started working up from there. That first cherry from Spain was probably the size of a pencil eraser.
Reporter: His daughter continues the work, and they’re getting closer to a commercially viable variety. But time is running out, and ultimately, they’re constrained by the genetics of the fruit.
Grant: Within limits, we can breed new varieties that maybe adapted to this kind of environment – within limits. Beyond that range, we’re done.