While the aspens and cottonwoods have lost their leaves in preparation for winter, Colorado’s slopes still thrive with an abundance of evergreen conifers. One pine stands out in a few isolated locations throughout the region, reigning over others for its ability to thrive for thousands of years on exposed, windswept slopes. Known for their astonishing longevity, bristlecone pine trees are found between 7,500 and 12,000 feet, where few other plants can thrive. In Colorado, Rocky Mountain Bristlecone Pines (Pinus aristata) grow in a few isolated locations. A closely related species, the Great Basin Bristlecone Pine, is found further west in California, Nevada, and Utah. While the two trees are very similar, they can be distinguished in a few ways. The Rocky Mountain bristlecone pine is found only in Colorado, New Mexico, and Arizona, so their ranges do not overlap at all. The Great Basin bristlecone pine is longer living and claims the title of oldest tree with an individual known to be over 5,000 years old. The Rocky Mountain bristlecone pine doesn’t live quite as long, but can still thrive for well over 1,000 years, and there are at least four individuals in Colorado more than 2,100 years old on Black Mountain. This means these trees were just little seedlings beginning to grow when the Great Wall was being built in China and the Roman Empire began to rise. These ancient, stoic trees hold much history in their rings.
Bristlecone Pine under the milky way.
Growing on windy slopes, bristlecone pines appear to almost defy gravity, sometimes growing completely sideways from being blown in the wind throughout their life. On harsh, exposed slopes, little else can survive, so bristlecone pines are not threatened by competition for nutrients and water. They also grow extremely slowly, and their short, bottlebrush-like needles can survive for up to 30 years, so they are able to conserve energy which contributes to their longevity. Bristlecone pines are a testament to resiliency, surviving even when 90% of their bark has been lost, relying only on a small strip of bark under which nutrients and water are transported and fighting off disease with large stores of resin.
Being so long-lived, bristlecone pine trees are incredibly helpful in dendrochronology, the study of tree rings, often in relation to historic events and environmental changes. Scientists use a tool called an increment borer to take pencil width samples of a tree to its core, and use these samples to date trees and study historic events and climatic patterns. These samples can help scientists learn about historic weather conditions, like rainfall, wind, and soil and air temperature.
Bristlecone Pine - Rocky Mountains.
As a North Carolina native and longtime tree lover, I was so excited when I finally got to meet some bristlecone pines. If you’re keen to meet some of these ancient giants, you don’t need to travel too far. The easiest-to-reach bristlecone from the Eagle Valley is at the top of Coffee Pot road at the Deep Creek Overlook. If you’re hoping to see a whole bristlecone pine community, you can travel to Alma and visit the Windy Ridge Bristlecone Pine Scenic Area, which is where I got my first glimpse of these spectacular trees.
Standing amongst bristlecone pines, living relics of the past, present, and future, is a feeling like nothing else. It’s humbling to be immersed amongst thousands of years of history. The trees' gnarled trunks show off their adaptability, while their bluish purple cones give hope for another generation of thousand year old trees.
Resources
https://www.fs.fed.us/database/feis/plants/tree/pinari/all.html
https://www.5280.com/2017/07/colorado-by-nature-bristlecone-pines/
https://www.lamtree.com/rocky-mountain-bristlecone-pine-pinus-aristata/
https://www.livescience.com/48344-bristlecone-pines-photos.html
Marin Harnett is a Naturalist at Walking Mountains Science Center and longtime tree hugger. She feels most at home in the forest and is on a mission to meet and learn to identify as many trees as possible.
