Strites' Orchard

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(Gallery by Dan Gleiter | dgleiter@pennlive.com)

Could one of life’s simple pleasures, the apple, be endangered by changes in our climate?

It could, according to some experts, who maintain that apples, like other fruit, depend heavily on a certain amount of what is called “winter chill,” before they bloom in the spring.

“If there’s not enough winter chill that happens in a certain year there can be anywhere from a decreased production of fruit to a complete crop failure,” says Evan Girvetz, the senior scientist on climate change for the non-profit Nature Conservancy.

If that were to happen, it would be troubling news for the state’s apple industry, which according to the Pennsylvania Apple Marketing Program is the fourth biggest apple producer in the country.

Apples grew on some 21,000 acres in the state in 2011, and produced about 11 million bushels, according to the program.

While Dauphin County is home to the locally well-known Strites’ Orchard, it is not on the list of the state’s leading apple growing regions. Nearby Cumberland County is, however.

The state’s apple crop drew the attention of the authors of two reports that attempt to outline possible consequences of a warming climate in Pennsylania.

Both the U.S. Environmental Protection Agency and the non-profit Union of Concerned Scientists say apple growing could be affected by warmer temperatures.

“High value fruit crops may no longer experience the winter chilling conditions required for optimal fruit production, and may also face increased pressures from insect pests,” says the concerned scientist report, first published in 2008.

Those fruit crops could also include grapes, which according to a Penn State report grow on about 12,000 acres in the state, most of them along the shores of Lake Erie and which are used for juice and jelly. There are also about 2,800 acres of land used to grow wine grapes around the state.

“The wine industry is small relative to other traditional commodity crops in Pennsylvania, but has a growing impact on the state’s economy,” the Penn State report says.

Like most people in agriculture, Jon Strite keeps a sharp eye on the weather from the orchard he and his family run in Lower Swatara Township.

He says he and others talk about the climate, but, “It’s hard to know what’s accurate, what’s true, what’s not.”

“It certainly seems like the past couple of years we’ve had some pretty extreme weather,” he says, pointing to a very early and warm spring in 2012, and the much cooler conditions so far this year.

He says the orchard, which bears his family name, keeps accurate records on the weather, which he checked during the warm days of the spring of 2012.

“Going back to 1914, I couldn’t find one where we started that early,” he says.

Still, Strite doesn’t see predictions of a warming climate to be a game changer so far.

“As long as it just happens slowly, you can adjust to it,” he says. “What are you going to do? There’s nothing I can do really to change it.”

The Nature Conservancy’s Girvetz says a global analysis the conservancy has done shows a good part of Pennsylvania to be in the region where there could be a decrease in what is considered a safe level of winter chill.

The model, he explains, assumes that growers may face inadequate winter chill once every 10 years.

“What it’s saying is that the level of winter chill is going to decrease from 10 percent to 30 percent,” he explains.

He says remedies for growers are not out of reach.

Different types of apple trees require different levels of chilling, he said.

So, growers could look for trees that do well in warmer conditions, pointing to differences in varities in Washington state compared to warmer California.

“There are going to be winners, and there are going to be losers with climate change and a lot of the winners are going to come from being aware of what types of changes they need to make,” he said.

“The worst thing we can do is to ignore the science that is clearly being laid out there to start preparing for the future,” he cautions.

None of which addresses the primary concern of Penn State Professor Greg Krawczyk, who is a fruit tree entomologist.

He said warmer weather will bring more insects to feast on fruit trees, he warns.

Moreover, even the existing 10 to 15 species of insects may well be more bothersome as temperatures rise.

That’s because of the likelihood that warmer weather would allow those species to reproduce more in one season.

“If we get warmer,” he says, “we might have to deal with a higher number of those generations. They would start earlier and possibly go longer during the fall.”