Climate change is hampering US apple quality and production: study

A new study has found that many of the nation’s largest apple-producing regions face challenges in crop growth and development due to the impacts of a changing climate.

While apple orchards across the country have become increasingly vulnerable to warming trends, the three top-producing U.S. counties are among the hardest hit, according to the study, released Monday inEnvironmental research papers.

Topping that list was Yakima County, Washington, home to more than 48,800 acres of orchards, which showed worrisome signs in five of six metrics analyzed by Washington State University scientists. Next were Kent County, Michigan, and Wayne County, NY

“We shouldn’t take for granted the delicious apples we love to eat,” Deepti Singh, a Washington state climate scientist, said in astatement. “Changing weather conditions in various parts of the growing cycle may increase threats to apple production and quality.”

Worldwide, it is currently the US third place among apple exporters, behind the European Union and China during the 2022-2023 season, according to the US Department of Agriculture.

At the state level, Washington is the largest annual producer, followed by Michigan, New York and Pennsylvania. The main markets for US apples are Mexico, Canada, Taiwan and Vietnam.

Using both historical trends and climate metrics, Washington State scientists evaluated six metrics that could affect apples over four decades, from 1979 to 2022.

Metrics included the number of extreme heat days, warm nights and cold days, as well as the number of cold hours required for a tree to go dormant, the last day of spring frost and the number of “growing degree days” or the previous ones. a certain temperature that favors the growth of the apple.

Changes in these metrics, the authors explained, can alter when apple flowers bloom, while increasing the risk of sunburn on apples and influencing appearance and quality.

According to the study, the western United States has experienced the strongest detrimental changes across multiple metrics.

Making these developments more complex is the fact that apple trees are perennial, meaning they bear fruit for many years.

“What happens in different seasons can affect the long-term health as well as the performance and productivity of the apple tree during that specific season,” said co-author Lee Kalcsits, a Washington State tree physiologist. in a statement. “It just keeps going around in a cycle.”

With these cyclical side effects in mind, growers in Washington state now use netting and evaporative cooling to prevent sunburn, according to Kalcsits.

The researchers also stressed that not all observed climate changes have negative impacts on apple cultivation, as some regions are benefiting from the changes.

“Fewer cold degree days and an earlier last frost day could be beneficial by reducing the exposure of apples to freezing temperatures by allowing the use of less cold-hardy crop varieties,” the scientists said.

“However, it could also decrease plants’ cold hardiness, increasing vulnerability to extreme cold events,” they added.

Co-author Kirti Rajagopalan, a biological systems engineer at Washington State, described Washington as an ideal case study, especially because parts of the state endure hot summers.

“If we can manage it here, it’s likely to be manageable elsewhere,” Rajagopalan continued.

Looking ahead, the authors stressed the importance of tailoring adaptive measures to the different stages of apple growth, an effort that Singh said could “minimize overall harmful impacts.”

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