By Robin Rivet.
Have you ever pondered what it would be like to live for 1000 years? What about 4000, or even 5000 years? There are such trees. Ancient bristlecone pine trees, or Pinus longaeva specimens, in the Inyo National Forest of Northern California are testaments to longevity. They are considered the oldest, non-clonal life forms currently living on our planet. If only they could speak…
As this text gets published, they are alive today, but were born when the printing press wasn’t even a remote idea, and paper hadn’t yet been conceived—never mind digitization. There was no need. The Sumerians hadn’t perfected the first written language. These trees were born before England's Stonehenge, the great pyramids of Egypt, and the Olmec civilization in Mexico. The ancient empires of China, Greece, and Rome all came and went; so did Christ, Moses, Buddha, and Muhammad. Meanwhile, these bristlecones remained standing, and grew in seemingly inhospitable locations, dominated by dolomitic, alkaline soil; albeit with few plant competitors.
Humans even named one of them “Methuselah”, after a famously long-lived person from the Hebrew Bible. The Methuselah bristlecone was cross-dated to be 4850 years old, although the biblical Methuselah supposedly died after 969 years, and there’s understandable dispute about that human age. Just ask Noah, his biblical grandson, who allegedly witnessed an immense global flood of epic proportion. No matter. These trees survived it all, perhaps because they thrived at 11,000 feet. Those extraordinary human tales may have reasonable explanations in how calendars and time were measured differently long ago, but modern tree ring research has unlocked the true age of the Great Basin, Foxtail, and Rocky Mountain bristlecone species—and it’s startling.
To attain a tree’s age, the science of dendrochronology matches up tree rings that pinpoint specific historic drought years, seasonal fluctuations, unusual growth spurts, and even forest fires, from one tree to the next. Rings extracted from cores of living trees are matched with cross-sections from ancient wood buildings and older downed deadwood. Together they create an annual historic record of deposited cambial growth with repeating ring patterns visible across many species and eras. Eventually a timeline is formed that can be used with some degree of accuracy to pinpoint the birth and death of most all tree specimens. (See illustration below, courtesy of ALPECOLe.) Currently, the oldest bristlecone was verified in 2012 to be 5062 years old, and it still lives in the White Mountains of California. For an arborist like me, visiting these trees recently was like a trip to “Tree Mecca”. It put our frail human existence into great perspective.
Why should you care? Not only are trees extremely beneficial to the ecology of our planet, but the fact that so many have endured for so long in excruciatingly hostile climates and soils might give us humans a clue about how we should adjust to our rapidly changing environment. And ponder this: in contrast to the long-lived bristlecone pines, suburban and urban trees have a life expectancy of less than 30 years, and that we should not ignore.
Member Robin Rivet is an ISA Certified Arborist, UCCE Master Gardener, and City of La Mesa Environmental/Sustainability Commissioner. Contact her at treetutor@gmail.com.