Fungus threatens Rocky Mountains’ ancient bristlecone pines |

Fungus threatens Rocky Mountains’ ancient bristlecone pines

Bruce Finley
The Denver Post

An exotic fungus spreading southward through Rocky Mountain forests is threatening Colorado’s oldest trees – the gnarled limber and bristlecone pines that can live longer than 2,000 years.

White pine blister rust fungus afflicts hundreds of those trees on national forest land and in the Great Sand Dunes and Rocky Mountain national parks.

There is no known cure for the fungus, which penetrates pine needles, then covers branches with clamshell-shaped cankers and orange pustules, eventually girdling tree trunks.

“This is tragic. These trees cling to the highest peaks and the high, windy ridges across the Rocky Mountains. White pine blister rust . . . is going to be transforming the nature of our highest forests,” said Jeff Mitton, chairman of the University of Colorado’s Department of Ecology and Evolutionary Biology.

In Montana’s Glacier National Park, the fungus has killed half of the whitebark pines (a relative of limber and bristlecone pines), and nearly all are infected, Mitton said.

Some limber and bristlecone pines in Colorado that the fungus threatens were growing at the time of the Roman Empire, he said.

As the fungus spreads, its spores apparently carried and deposited by the wind, researchers are brainstorming survival strategies.

Unlike the pine beetles, which occur naturally as part of Rocky Mountain ecosystems, the white pine blister rust fungus spread from Asia. Researchers say trees here have little ability to resist it and that once it infects them, it is fatal. The fungus apparently reached North America decades ago when timber companies, replanting their land after logging, imported infected seedlings.

Bruce Finley: 303-954-1700 or

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