Suzhou, China ? The struggle between the old and the new in China — a tug of war affecting family life, the economy and the whole society — comes into focus in the office of Du Guo-Ling, the vice mayor of this city and keeper of its cultural heritage.

Suzhou, a city of almost 6 million residents, is located west of Shanghai in the delta of the Yangtze River. It is famous for its gardens, which combine limestone rocks, water, bamboo and other plants in a landscape that changes at every turning. The canals that give the city its special look go back to the 6th century, when it was known as the kingdom of Wu.

The center of the city — with the famous gardens and a nine-story pagoda — is listed by the United Nations as a World Heritage site, and special permission is required for any construction within that protected zone.

But the environs are totally modern China. Two giant industrial parks — one financed by Singapore developers, the other by Chinese entrepreneurs and the local government — surround the historic district on the east and west. The authors of the Blue Guide to China complain that “in order to improve communications between the two zones, a motorway was driven right through the center of the historic city.”

Du told a group of visitors the other day that no further incursions will be allowed. A determined-looking woman with penetrating dark eyes, she spoke with passion about her visit to Suzhou’s sister city of Venice and the pledge she and its mayor had made to each other to protect the legacy of their ancestors.

“We have 2,500 years of recorded history here,” she said. “This is the best-preserved ancient city in China. We are determined not to lose it.”

But Suzhou, like the rest of coastal China, is equally determined to embrace the new economy and the riches it promises. After walking her guests through one of the oldest gardens in the historic city, Du steered them out the controversial freeway to one of the two stunningly landscaped industrial parks.

It was a sunny, breezy Sunday, and all along the shore of Golden Rooster Lake, newly married brides and grooms were celebrating their nuptials with family and friends. The brides in white, Western-style gowns were being twirled in the air by their proud husbands, while children mugged for family cameras on the animal sculptures scattered throughout the park. It was a thoroughly happy, middle-class scene.

Scattered on the fringes of the park are a half-dozen corporate headquarters towers, with their curved facades mimicking downtown Los Angeles or midtown Manhattan. And stretching away to the east, mile after mile, are the workplaces of the new economy — assembly plants for Panasonic and Nokia, labs for Emerson and Zeiss and dozens of competitors. A bit farther back from the four-lane roads stand tall apartment buildings for the thousands of workers here or soon to come.

Du spoke of the high-tech suburb’s attractions as enthusiastically as she recounted the charms of the ancient gardens. “We are determined to assure that the development is well-rounded,” she said. “Not just factories and offices, but schools for the workers’ children and clinics. And above all, a healthy environment.”

But, she conceded, the economy’s growth is like a juggernaut, testing the planning capacity and controls the city government tries to maintain. Last year, Du said, Suzhou attracted $6.8 billion in foreign investment, $1 billion more than its giant neighbor, Shanghai. “We have the highest degree of globalization of any city in China,” she bragged. “More and more industry is locating here, because they can ship their products from Shanghai but avoid the crowding and the costs and the pollution.”

But can Suzhou control its own future — and protect its past, she was asked. “That is up to international business,” she replied. “This year, we had $2.8 billion of investment in the first quarter, equal to what we had in the first two quarters of last year.” The economic engine is racing faster and faster.

And the social problems grow apace. There are almost 3 million “recent arrivals” in Suzhou, attracted by the prospect of jobs paying more than they can possibly make on the farms from which they come. “That is our biggest challenge,” Du said. “Industry naturally wants as many people for the hiring pool as possible, but the city has to provide services for them and their children, whether they find work or not. And because we are a ‘wealthy city,’ we do not get help from Beijing.”

All this makes her job a challenge — even as she tries to keep commercialism from corrupting the historic city. And that is tough. Many of the pedicabs in old Suzhou now bear the Golden Arches imprint of McDonald’s.

— David Broder is a columnist for Washington Post Writers Group.