Big Blue, Meet Old Blue: USU Researchers Record World's Oldest Known Colorado Blue Spruce

At the time of year when people haul their favorite tree indoors to adorn with lights and garlands, a certain Colorado blue spruce is keeping a low profile — at least as low as its 457 years of growth will allow. A team from the Quinney College of Natural Resources recently identified the tree (they christened it “Old Blue”) as the oldest known Colorado blue spruce in existence, and it lives in Utah.

Inside the boundaries of Cedar Breaks National Monument, Old Blue is actually at no risk of becoming a Christmas decoration. But it does face other threats just as serious, if more slow-moving. As the region’s climate gets hotter, and precipitation patterns more difficult to predict, Utah’s forests face a slew of challenges, including bark beetle infestations, drought and wildfire. Old Blue is the type of tree the research team works to identify and monitor, because it is a “survivor,” said Jim Lutz, author of recently published research on the topic.

Lutz, Joseph Birch and Justin DeRose from USU’s Department of Wildland Resources focused on Colorado blue spruce and Engelmann spruce as a foundational species in these subalpine ecosystems.

“Old trees are vitally important, because they are tough and provide unique habitat,” said Joseph Birch, lead author on the research. “They have genetics that have let them survive through all sorts of circumstances over hundreds of years. They are ecological winners, and they pass on these traits through tens of thousands of cones over the course of their lifetime.”

Colorado blue spruce is not an especially common tree species in the Rocky Mountains, but times are changing, Lutz said. Warming and more variable climates threaten to upend historical tree ranges, and the team is working to identify which kinds of tree species will likely expand under the changing climate. They’ve identified Colorado blue spruce as a candidate that could be more suited to the emerging conditions as things shift.

For instance, that particular species is less susceptible to succumb to spruce bark beetle attacks. There was a large-scale outbreak of these insects in the 1990s that killed almost all of the mature Engelman spruce in the region. Spruce bark beetles are native and they aren’t going away anytime soon, Lutz said. As temperatures warm and summer seasons expand, the beetles are now able to fit one complete life cycle into each season, rather than needing two years. Their impact is on the rise.

We need to decipher how individual tree species respond to these kinds of changes, so that researchers can predict future big-picture changes in forests, said Birch, especially for these old trees. To identify Old Blue, the researchers pulled a core sample that showed the tree-rings and painstakingly counted backward the tree’s remarkable lifetime — not an easy task.

“Considering that Old Blue germinated around the same time that Shakespeare was born, we might remember the words of The Bard now,” Lutz said. “‘All the world’s a stage, and all the trees merely players.’ This tree, and others like it, may play a part as an overlooked species capable of providing clues to past climates and information about what the future climate might create in Utah forests.”