World’s Oldest Trees: Clues to Earth’s Climate History

Alex Ross’ article in The New Yorker entitled “The Past and the Future of the Earth’s Oldest Trees,” published on 13 January 2020, talked about the Great Basin bristlecone pines Pinus longaeva in the White Mountains in eastern California. Three individual pines from this area have been dated to be more than 4,500 years old, and scientists believe there may be much older specimens in the area.

The first is called Methuselah, in reference to the biblical figure believed to have been the human who lived the longest at almost 1,000 years old. The second named Prometheus was believed to have been older than the one named Methuselah, but was unfortunately felled in 1964 after a core sampling had gone awry. The third, unnamed, is the oldest Great Basin bristlecone pine scientifically dated at 5,071 years. It is the oldest known non-clonal tree to date.

Pinus longaeva, the Great Basin bristlecone pines.
Photo source: Wikimedia Commons.

The age of these trees is certainly impressive: to be alive for thousands of years; to have been present as kingdoms and civilisations rose and fell; to have witnessed—and survived—global climate events. For the latter, these trees must have evolved great coping mechanisms to survive—and continue thriving—this long. Its gnarled appearance plays in one’s imagination; the phrase “twisted by time” seems so apt.

Pinus longaeva trees have another thing seriously exciting about them. Scientists think these ancient trees may have a way of telling us about events that happened in the past. Their tree-rings, aside from being a record of their age, may also provide a record of historical climate data.

In 1904, astronomer Andrew Ellicott Douglass studied the variations in the width of tree-rings of the giant sequoias (then thought to be the world’s oldest trees), and essentially founded dendrochronology. With the Pinus longaeva, scientists have observed a disruption in the usual pattern of its tree-rings—developing “frost rings”—during major climate-changing events, such as volcanic eruptions. However, with the age of Pinus longaeva trees, their stems have also borne the scourge of the elements, exhibiting fractures and even erosions. The oldest ones of their tree-rings may not be intact.

“Something that began growing at the time of the Pyramids has a right to say stuff. It gets to comment.”

– Dr. Charlotte Pearson, geoarcheologist and dendrochronologist,
as quoted in Ross, Alex, “The Past and the Future of Earth’s Oldest Trees,” The New Yorker, 13 January 2020.

This is really exciting stuff despite its limitation. Scientists are now exploring the relationship between bristlecone pine tree-rings and radiocarbon dating. What they could find may have compelling implications on how we understand ancient history and civilisations.

There have been alarms raised over climate change pushing these ancient trees to extinction. However, Ross reported that tree scientists think the Pinus longaeva trees are not in any imminent danger. To have lived so long and survived many climatic catastrophes in history, it is indeed quite possible that these trees will outlive humanity, as Ross opined.

Burro’s Tail

Oh, joy! My leaf cuttings of Sedum morganianum, commonly known as Burro’s Tail, have grown. All three leaf cuttings do not anymore just have a little bump at the attachment area, but now have leaves—proper, tiny leaves! It took them about five weeks to go from having just a bump to this stage.

Funny how people name things. Or, plants, in this case. Burro’s Tail. Today, seeing that the leaf cuttings have thrived, I googled to know more about this particular succulent. I learned that this succulent is also called by other common names, among them: Donkey’s Tail, Horse’s Tail, and Lamb’s Tail. It seems people (the ones who have given this succulent its name) are quite agreed that the trailing stems of Sedum morganianum look like some kind of tail; they are just not sure what kind of animal’s tail it is.

Sedum morganianum mature plant grows trailing stems, 30cm or longer, densely packed with globules of fleshy blue-green leaves. The one I took the cuttings from must be a young plant, its unpruned stems not even reaching 10cm yet. I am looking forward to seeing these three plantlets grow. Hopefully in six to eight weeks time, their leaves will have grown more substantial and I can already transfer them to their own pots. For now, all that’s needed—aside from ensuring they don’t dry out—is to be patient.