Denver, Colorado - Strands of distressed, red pine trees across northern Colorado and the Front Range are a visible testament to the bark beetle infestation that officials said will kill most of the state's lodgepole pine trees within 5 years.

The infestation that was first detected in 1996 grew by half-million acres last year, bringing the total number of acres attacked by bark beetles to 1.5 million, state and federal forestry officials said Monday.

"This is an unprecedented event," said Rick Cables, Rocky Mountain regional forester for the U.S. Forest Service.

The fire potential will increase as trees retain their needles for a couple of years after beetles attack, said Bob Kane, regional entimologist with the Rocky Mountain Region of the U.S. Forest Service. When the needles fall, the danger will decrease, and spike again when the trees fall in about 10 years, Kane said.

Officials said the infestation has been concentrated in five northern Colorado counties straddling the Continental Divide and has since spread to the Front Range and southern Wyoming. The counties affected are Boulder, Chaffee, Clear Creek, Gilpin, Lake and Larimer counties.

Boulder and Larimer counties, both east of the divide, had a 1,500 percent increase in the number of acres taken over by the beetles last year, which are preying on the tall, slender lodgepoles left vulnerable by warm winters and drought.

About 8 percent of forest landscape in Colorado are lodgepoles, said Ingrid Aguayo, forest entimologist with the Colorado State Forest Service. Aguayo said the epidemic doesn't mean it's the end for lodgepoles, but rather part of the regeneration process.

"A lot of people think this is the end of the forest, but as an entimologist, I see it as the beginning," she said, pointing out seedlings about five inches tall are already sprouting in parts where the beetles have run their course.

"It's not going to be a moon landscape like a lot of people think," she said.

In some cases entire mountainsides can be turned red as trees struggle to survive the infestation, affecting the scenic vistas along stretches of mountain highways. Eventually the trees will turn grey after the needles fall, Kane said.

It could be up to 50 years before lodgepoles return to their population before the bark beetle infestation, Aguayo said.

Jim Maxwell, a spokesman for the U.S. Forest Service, said the lack of trees will increase the water supply by 30 percent on National Forest Lands for about 20 years because trees will no longer be pumping water out of the soil.

Susan Gray, group leader for forest health management with the U.S. Forest Service Rocky Mountain Region, said only 20-below-zero temperatures for a sustained period can kill the beetles.

"Unfortunately, it hasn't been cold enough long enough," she said.