A mountain pine beetle infestation that has already killed off billions of trees in British Columbia is threatening to take over Alberta's jack pine, marking the start of a deadly cross-country trek.

Each mountain pine beetle is the size of a grain of rice, but the voracious insects have already devoured an area of B.C.'s forest the size of Iceland.

Adult mountain pine beetles prefer large diameter trees, according to the Canadian Forest Service.

Another two million hectares in Alberta are now at risk, and the infestation could spread to Canada's boreal forest.

"It likes all pine species and we've recently discovered this includes jack pine, which is a component of the boreal forest," said Allan Carroll, a research scientist with the Canadian Forest Service.

Mountain pine beetles began invading parts of Alberta four years ago. If the beetles jump from the lodgepole pine to the jack pine, an infestation could wipe out billions of trees all the way to the East Coast, he said.

The Rockies at risk

The frontlines in this battle are the northeastern slopes of the Rocky Mountains.

'Thanks in no part to Smokey the Bear.'-Warden Dave Smith

Jasper National Park warden Dave Smith said because Canadians are so good at preventing fires, the forests are old, weak and susceptible to infestation.

"Thanks in no part to Smokey the Bear. Smokey has done a tremendous disservice to our forest health by promoting the notion all fire is bad."

Global warming has also helped the pine beetle along, as cold winters can help slow infestations.

If enough infested trees can be removed, it may prevent the kind of destruction British Columbia is experiencing from occurring in Alberta and the rest of Canada, said Carroll.

Decimating forests

The beetles are less than one centimetre long, but they are one of nature's most efficient predators.

Several thousand beetles burrow under the bark, laying eggs and destroying a valuable, 80-year-old tree within days. When the tens of thousands of eggs hatch, they decimate the next stand.

Alberta has been falling and burning individual trees to kill the bugs, and is planning a large-scale burn in Willmore Wildnerness Park in August.

The federal government is spending $40 million to try to slow the spread of the infestation.