REIMS, France (Reuters) - In the hilly region of Champagne in eastern France, winegrowers are bringing in grapes early this year for a harvest they expect to be one of the best in a decade.

The harvest began at the end of August for most vineyards instead of the usual September after a rainy winter and a summer heat-wave look set to yield a bumper crop and high-quality bubbly.

Champagne wines are expected to see a sharp rise in production, up 56 percent from last year to 3.5 million hectoliters, after several years of unsatisfying crops due to bad weather.

“The last few years have been tough, this year is expected to be exceptionally good so we are very happy,” said the president of Champagne winegrowers’ union, Maxime Toubart.

While most Champagne winegrowers are celebrating an exceptional harvest, others see the beginning of long-term change in the region.

Winegrower Eric Rodez, who runs his own vineyards and operates a 1936-built traditional press, is convinced climate change is making earlier harvests the norm.

“Because of climate change, we have to be prepared to regularly harvest in August,” Rodez said, noting that starting earlier is the only way to keep the uniqueness of the Champagne wine, produced with grapes that cannot be too ripe.

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The trend has already emerged over the last decade with three harvests starting in August rather than September. Thirty years ago, harvests in October were not unheard of.

According to Toubart and the Champagne winegrowers’ union, the more than 15,000 Champagne winegrowers will likely harvest between 13,000 and 16,000 kilograms (29,000-35,000 pounds) of grapes per hectare (2.5 acres).

That leaves a comfortable margin for producers to use only the best grapes and rebuild reserves used up in recent years since the industry has agreed this year to bring 10,800 kilograms per hectare to market.

“We have never experienced this before in the Champagne region, in terms of quantity and quality,” said Jean-Marie Barillere, president of the Champagne houses’ union.

“This will enable us to put into cellar amazing wines which will be on the market in three years,” he added.

Each year, 310 million bottles of French Champagne - whose geographic designation is strictly controlled as a brand - are sold worldwide while more than a billion are stored in cellars waiting for the right moment to be savored.