Mad About Science: Great Basin bristlecone pines

By Brenden Bobby
Reader Columnist

This hot take might prompt a few angry letters to the editor: California gets a bad rap. Think what you will about its politics, but the natural wonders of the state are undeniably special and awe inspiring.

Last year, I spent a few hours walking among the redwoods. It was a transcendental experience, walking between towering giants whose lives began as seedlings around the time our species was inventing paper. The peace and serenity found at the heart of the Ossagon trail was something more people should truly experience to bring themselves back to the roots of what it means to be human.

California is home to a number of incredible trees, from the Sierra redwoods to the colossal sequoias to the topic of today’s article: the Great Basin bristlecone pine.

The Great Basin bristlecone pine, Pinus longaeva, might not look like much when comparing it to the massive redwoods and sequoias, but it is a unique addition to the mountainscapes of California, Nevada and Utah. It’s a notably ugly tree, often appearing gnarled and wreathed in dense, long-dead bark with small tufts of fresh growth emerging from the crevices. You’d be forgiven for passing this tree without so much as a second thought.

The longevity of these trees, referenced in its scientific name, is what makes them truly special. The oldest recorded bristlecone pine, named Methuselah, is confirmed to be at least 4,854 years old. This makes Methuselah the oldest non-clonal organism on Earth. You might be wondering what that means.

Clonal organisms are able to reproduce by cloning themselves. A perfect example of this is Pando, one of the oldest and heaviest living organisms on Earth. Pando is a colony of quaking aspen trees in Utah. At a glance, it’s easy to think that this is simply a forest of trees, but they’re all connected by a single root structure. Pando has been growing and sprouting clones of itself for the past 14,000 years, replacing dead trees with fresh ones from the same core roots.

This is fairly common in the plant world, and a trait that humans have adopted for their own benefit in agriculture. Seedless grapes cannot reproduce, as they are by definition seedless. There are two methods for growing new seedless grape plants that use a very similar function. One method is to trim a limb from an established but dormant plant, wrap it in damp paper towels and plastic bags, and leave it in a warm place over the winter. Closer to spring, you can unwrap the cuttings and see a chalky powder growing near the base of the cutting, and maybe even some roots. You can plant these and grow a clone of the parent plant. There are a number of books on how to do this in more detail at the library.

Another process similar to cloning is grafting. This is when you carve a notch into an established plant and take a cutting from the plant you wish to propagate. Put these two together and seal them up, and with a little luck the plant should graft to the host. This is extremely common in orchards to fast-track the fruiting process.

The Great Basin bristlecone pine is neither of these things. The tree harbors some secrets for tapping into near-immortality. The biggest secret is the climate in which it lives. These pines live high on mountains, where the air remains colder than you’d expect in a place like the Golden State. This reduces a number of issues that trees in more temperate climates face, including insects, rot, mold and other plants. All of these together reduce the likelihood of the pines facing the biggest threat to California’s trees: fire.

Another secret to the pine’s longevity is its extremely slow growth. While the tree reaches maturity after two years, which is uncharacteristically rapid for most pines, it grows very slowly and creates thick layers of dense wood to shield its core from the elements. Interestingly, the outer portions of the tree dying and hardening are also a part of the tree’s survival mechanism. It effectively builds armor, then stops delivering energy and resources to those outer portions to help sustain itself.

This slow-growth and longevity is on full display in the tree’s needles, which are kept alive longer than the leaves and needles of every other tree in the world. Recent projections suggest that these needles remain active for up to 40 years. This allows the tree to devote relatively few resources to the needles by not having to cycle them regularly like our local ponderosa pine trees.

Finally, one of the most amazing things about this tree is the very thing that it’s named for: its cones. The bristly cones go through a colorful transformation, beginning as bright red conical pollen buds that slowly transform into a deep purple pod before shifting into a spiky scaled brown cone that looks fairly similar (to the untrained eye) to the cone of a ponderosa pine.

You may be wondering how we deduce the age of these trees, and worry about some strong-armed lumberjack felling trees as old as human civilization just to count the rings. Don’t worry, scientists have a specialized boring tool that can dig a long sample from the tree that allows them to count the rings without doing irreparable damage to the plant. It’s not much different from going to the doctor and getting a biopsy.

Stay curious, 7B.