Alberta Premier Ed Stelmach defended his province's development of crude from Canada's massive oilsands as environmentalist complaints trailed him to the Western Governors' Association meeting last week in Wyoming.

Stelmach said he expects his province's oil industry to be scrutinized because it's the top source of imported crude oil to the United States. Alberta exported 1.35 million barrels of crude oil a day to the U.S. in 2006, making up 13 per cent of U.S. crude imports.

"Being the No. 1 supplier to the United States, we expect that we'll be drawing attention, simply as a result of that," Stelmach said. "We're continuing to work to be leaders in greening our growth; we will lead in that policy development with or without the federal government. We're willing to make the investments."

The Natural Resources Defense Council (NRDC) and other groups took out an advertisement in the Casper Star-Tribune, Wyoming's largest newspaper, criticizing the impact of Alberta's oilsands development on forest land and the emissions the crude produces as fuel.

The groups also sent letters to all the governors in attendance at the Western Governors' Association meeting.

"We look at this as a time when we need to be very concerned about climate change," said Josh Mogerman, NRDC spokesman. "This is a double whammy of creating more (carbon dioxide) and also knocking down one of the biggest forests in North America that absorbs (carbon dioxide)."

Stelmach said Alberta has pioneered carbon-capture efforts, was the first North American jurisdiction to impose a levy on carbon emissions and has worked to reduce energy consumption in the province.

Montana Gov. Brian Schweitzer said the oilsands are an important fuel source for the United States. While it may produce some environmental challenges, so do sources such as coal and nuclear power, he said.

"This oil replaces oil that we're buying from dictators around the world," Schweitzer said.

"We will never have to send troops to the border between Montana and Alberta to protect that energy supply. These are good trading partners."

"They're friends of ours. We will help them develop their energy and they will help us develop our energy."

The governors held three days of discussions on issues related to energy, climate change, water supply and wildlife habitat.