Bristlecone

May 27, 2024

Memorial Day (originally Decoration Day) is a federal holiday to commemorate military personnel who died serving in the US Armed Forces.  This began in 1868 and was observed on May 30^th until Congress standardized federal holidays in 1971, and it is now observed on the last Monday of May.  Many have taken to decorating the graves of family on this day as well.  As a contrast USA Today also published an article today commemorating tree longevity.  Scientists use dendrochronology (tree ring count) to determine age and the size of the rings is a sign of the tree’s endurance in the face of change.  Trees that survive through extreme weather, pests, diseases, and human interactions provide lessons that may protect future forests.  One Florida southern live oak (Quercus virginiana), named “Big Tree,” is over 400 years old.  It was struck by lightning at least three times and survived multiple hurricanes and yet remains healthy.  According to Guinness World Records, the oldest tree species in the world are the bristlecone pines, found in the White Mountains in California.

When I looked online, I found the bristlecone pine (genus, Pinus) covers three species of pine tree.  All three species are long-lived and resilient to harsh weather and bad soils, but Pinus longaeva is among the longest-lived life forms on Earth with examples more than 4,800 years old.  As the oldest known individuals, scientists study the trees to find how they live so long.  One study found bristlecone has higher levels of telomerase activity, which slows or prevents the attrition rate of telomeres, or the repetitive nucleotide sequences associated with proteins at the ends of linear chromosomes.  The Bristlecone is a “first succession” species and rapidly occupy newly opened ground (fires) but compete poorly in less-harsh environments.  Bristlecone grows in scattered subalpine groves at high altitude in arid regions of the Western US.  The three related species are the Great Basin bristlecone (Pinus longaeva) in Utah, Nevada, and eastern California, the Rocky Mountain bristlecone (Pinus aristata) in Colorado, New Mexico and Arizona, and the Foxtail pine (Pinus balfouriana) with two disjunct populations found in the Klamath Mountains (subspecies balfouriana) and the southern Sierra Nevada (subspecies austrina).  The species can hybridize in cultivation, but the ranges of wild populations do not overlap and they do not do so in nature.

Bristlecone pines are known to scientists as “extremeophiles” because they are slow-growing and can endure harsh environmental conditions, including cold temperatures, high winds, dry soils, and short growing seasons.  The world’s oldest living tree is “Methuselah.” The tree’s exact age is unknown, but the US Forest Service (USFS) experts believe it is around 5,000 years old.  Dendrochronologist Edmund Schulman found and named the tree in 1957.  The tree is named after a biblical figure who is said to have lived to 969 years.  The ancient tree dubbed “Prometheus” was cut down in 1964 (with USFS permission) that they later realized was an estimated 4,900 years old.  Methuselah is alive as of May 2024.  Officials do not provide photos or exact location of this oldest living tree to protect it from damage and human vandalism.

THOUGHTS:  Climate change is threatening the longevity of the Bristlecone along with many of the world’s oldest trees.  The Rocky Mountain population is severely threatened by an introduced fungal disease (white pine blister rust) and by mountain pine beetles (Dendroctonus ponderosae).  Climate change may also affect the species as temperatures have increased 0.9 to 1.8F (0.5 to 1C) over a 30-year period in the southern Rocky Mountain range, especially affecting trees in higher elevations.  Old specimens of bristlecone pine have survived previous warmer periods, but the loss of younger trees will affect genetic diversity.  Even the old trees will not survive increased forest fires.  Act for all.  Change is coming and it starts with you.