By David Ljunggren

OTTAWA (Reuters) - Canadian Prime Minister Justin Trudeau said on Wednesday he looked forward to working with Donald Trump after the businessman won the U.S. presidency in a victory that could hurt Canada's exporters and wreck plans to impose a national carbon price.

The left-leaning Trudeau, who supports free trade and higher immigration, is ideologically removed from the Republican U.S. president-elect.

"We share a purpose, our two countries. ... I'm going to work with (his) administration as we move forward in a positive way," Trudeau told a youth forum.

Trudeau's office said on Wednesday evening that the two spoke, reiterating the importance of the Canada-U.S. relationship and discussing areas of mutual interest

Trudeau also invited Trump to visit Canada and Trump reciprocated, Trudeau's office said.

Trump vowed on the campaign trail to revise or tear up the North American Free Trade Agreement (NAFTA) under which Canada sends 75 percent of its exports to the United States.

David MacNaughton, the Canadian ambassador to Washington, told reporters that he interpreted the Trump camp's comments on NAFTA as a desire to improve the deal. If Trump wanted to discuss changes, Canada would come to the table, he said.

"Anything can be improved, and we're open to having discussions," he said, but declined to give further details.

The challenge for Ottawa is that it had assumed Democrat Hillary Clinton would win and played down the need for a game plan for a Trump victory. Officials must now work out how Canada's export-reliant economy can maintain its privileged U.S. access.

Roland Paris, who served as Trudeau's foreign policy adviser until late June, said the prime minister should make the case for close economic ties.

"He needs to be thinking about mobilizing allies at all levels of the U.S. political system," he said.

A November study by Export Development Canada said exports to the United States could drop between 1.2 percent to 4.5 percent, depending on what approach Trump took.

The two nations are locked in a dispute over Canadian softwood lumber exports, which U.S companies complain are unfairly subsidized.

Trump has little sympathy for the Canadian position, and MacNaughton said he was optimistic he could strike a "sensible agreement" with the administration of Barack Obama.

The Trump win also could imperil Trudeau's plan to impose a carbon price as part of a commitment to meet international climate change goals.

Trump has said global warming is a hoax and if he dilutes America's commitment to combating greenhouse gases, it could make Canadian businesses less competitive.

Brad Wall, the premier of Saskatchewan and an opponent of the carbon price, said the idea made no sense when "our biggest competitor for investment and jobs is not going to have one."

(Reporting by David Ljunggren; Editing by Bill Trott, Jonathan Oatis and Kim Coghill)