CEDAR RAPIDS — In a move likely to calm diplomatic and trade concerns created by Donald Trump’s rhetoric during and after the presidential campaign, the president-elect has tapped Iowa Gov. Terry Branstad to be his ambassador to China.

Branstad, whose familiarity with the world’s second-largest economy includes leading six trade missions to China, has a long, personal relationship with Chinese President Xi Jinping.

“Branstad’s decades of experience in public service and long-time relationship with President Xi Jinping and other Chinese leaders make him the ideal choice to serve as America’s Ambassador to China,” Trump said Wednesday.

Branstad made his first visit to China in 1984 and has known current President Xi for more than 30 years.

That relationship and his experience trading with China “will serve him well as he represents America’s interests and further develops a mutually beneficial relationship with Chinese leadership,” Trump said.

Branstad, 70, the longest-serving state governor in American history, said he was “honored and humbled” to accept the nomination and the “extraordinary opportunity” it presents.

“I believe that the respect and admiration built over a decades-old friendship between President Xi and me gives me an opportunity to help the president-elect and serve Iowa, the United States and the world for the better,” Branstad said in a statement Wednesday afternoon.

His nomination appeared to sit well with the Chinese. At a news briefing in China, foreign ministry spokesman Lu Kang referred to Branstad as an “old friend” and said his “greater contribution to the development of China-U.S. relations” would be welcome.

“No matter who takes this position, we’re willing to work together to push the Sino-U.S. relationship to consistent, healthy and steady development,” Kang said.

That’s a change in tone from Kang, who called Trump’s recent phone call to Tsai Ing-wen, the leader of Taiwan, “petty.” Although the U.S. has relations with Taiwan, which China considers a rogue province, and the Obama administration is selling it military equipment, the call was not consistent with the United States’ “one China” policy of more than 40 years.

Earlier on the campaign trail and in Twitter posts, Trump attacked China for its trade and currency policies, as well as the way it has staked territorial claims in the South China Sea. He has threatened to slap tariffs of up to 45 percent on Chinese goods if Beijing didn’t “behave.”

In his statement, Branstad seemed to acknowledge there will be some hand-holding involved in repairing the relationship with China, which he said is at a “critical point.”

“Ensuring the countries with the two largest economies and two largest militaries in the world maintain a collaborative and cooperative relationship is needed more now than ever,” he said.

Branstad may be just the person for that role, according to a University of Iowa official who has traveled to China with Branstad on a trade mission.

Branstad’s appointment could help cool tensions that might have flared with heated rhetoric during the campaign season, said Downing Thomas, the university associate provost for academic affairs and dean of International Programs. Branstad’s relationship with Xi and the experience he has logged forging partnerships in the country could benefit both nations, he said.

“That steady-hand approach is the right one with China,” Thomas said. “It’s quite a good match for the Chinese mentality … which is about stability.”

John Stineman of the Iowa Chamber Alliance, seconded that thought but said the strength of the Branstad nomination is more than his relationship with Xi.

“Outside of a former U.S. trade rep, I don’t think there is anyone out there who has personally been involved in and negotiated more trade agreements than Terry Branstad,” said Stineman, whose organization represents the 16 Chambers of Commerce and economic development organizations in Iowa’s largest communities. “He’s well-qualified on the merits of his experience.”

The Branstad-Xi friendship dates to 1985 when Xi, then an up-and-coming Communist Party member and low-level agricultural official, lived with a Muscatine family while leading an animal-grain delegation. It has continued over the years as they have visited each other’s nation, including Branstad leading a China trade mission in November.

Branstad, whose son, Eric, directed Trump’s Iowa campaign, made an impression on Trump during the campaign, Trump's spokesman Jason Miller said. Even before the election, Trump appeared to have Branstad in mind for the China post. At a campaign rally in Sioux City just two days before the election, he referred to Branstad as “our prime candidate to take care of China.”

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The favorable impression may have stemmed in part from Branstad’s willingness to defend some of Trump’s controversial statements, including a suggestion that Muslims should be banned from entering the United States.

“I think what Donald Trump is doing is saying we need to take this threat seriously,” Branstad said after the Orlando nightclub shooting.

In addition to signaling that the president-elect’s relations with China may be more cordial and diplomatic than his campaign comments might indicate, the Branstad appointment should ease fears of a trade war.

This year, the U.S. has exported $92 billion worth of goods and services to China and imported $381 billion in Chinese goods. Iowa farmers and ag processors exported $2.3 billion in goods and $273 million in services to China in 2015, according to the U.S. China Business Council.

Branstad does have differences with Trump. He’s a supporter of the Trans-Pacific Partnership, a trade deal involving the United States and 11 Pacific Rim nations, but not China. Branstad sees it as key to expanding trade to that part of the world where soybean products are in demand and the appetite for meat is growing.

“For trade and the importance of that for Iowa, it’s a real positive having him be ambassador,” said Bruce Rastetter, president of Iowa’s Board of Regents, agribusiness mogul and Branstad confidante. In addition to agricultural trade, Rastetter sees a variety of potential benefits for the state and its public universities.

It’s not about Iowa getting a leg up on other states in terms of China trade, Stineman said, “but having the best possible person in the role to make sure the U.S. has a healthy trading relationship with China.”

However, he conceded Iowa “has a disproportionate opportunity when it comes to trade. We have more opportunity and more on the line.”

There’s more work involved in negotiating several bilateral trade agreements, which Trump prefers, than multilateral pacts such as the TPP, but Grant Kimberly of the Iowa Soybean Association said he takes the appointment of Branstad “as a good sign that Trump understands that China an important trade partner.

“We need each other, and it certainly helps to have Branstad with a personal relationship with Xi to have a good conversation about tough issues,” Kimberly said. “He can be a great go-between for everybody.”

Vanessa Miller in the Iowa City bureau contributed to this report.