Rocky Mountain Bristlecone Pine Pinus Aristata

There are three kinds of bristlecone pine trees that dot the landscape of the Rocky Mountains in the United States.  One is the common Pinus aristata variety in the southern Rocky Mountains, known as the Rocky Mountain bristlecone pine.  Another is the more famous Pinus longaeva (Great Basin bristlecone) in California, Nevada, Utah and other western states.  The third is Pinus balfouriana (foxtail pine) in California.

Pinus aristata range

The U.S. Forest Service states the Rocky Mountain bristlecone pine occurs in the southern Rocky Mountains of Colorado, New Mexico and Arizona.  The tree’s range extends from the Sangre de Cristo Mountains in New Mexico northward to Rocky Mountain National Park in Colorado.  This type of pine tree is found anywhere up to the top of the timber line on many mountains.   

Size and shape

In lower elevations, the Rocky Mountain bristlecone pine grows to an average of 40 feet tall.  Two extraordinary specimens in New Mexico are over 70 feet in height and 11 feet in diameter.  Largest specimens get to around 28 inches in diameter.  


Bristlecone pines grow slowly.  A tree with an average age of 200 to 250 years averages 16 to 20 inches in diameter.  These types of pines first generate seeds between 10 and 40 years old.  The predominant method for seeding new trees involves wind carrying seeds to new ground.  How fast these conifers grow depends upon the climate of the previous year.  Specimens have been studied for climatological purposes as some trees have grown to over 1,500 years old.  The oldest known specimen of Pinus aristata is estimated to be 2,500 years old in the southern Front Range in Colorado.  


Pinus aristata can become twisted and gnarled as they grow.  Many of the areas where these trees are found are protected on public lands in the United States.  Older trees often form irregular crowns.  Cones can vary from two to four inches.  Needles are thicker towards the end of branches and stay on trees anywhere from 10 to 15 years.


Bristlecone pines are not harvested in anyway.  Owning bristlecone pine wood is illegal in Arizona.  Although these trees are hardy and can survive in harsh conditions, their scarcity and slow growth necessitate protection on federal lands.

Other varieties

Great Basin bristlecone pines are known for their extreme longevity.  Some specimens have been documented at more than 4,000 years old.  Foxtail pines are found in two areas of California in several national forests.