Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news of fascinating discoveries, scientific advances and more.
Trees are believed to have originated hundreds of millions of years ago. Since then, there has been little evidence of ancient plant guardians.
Now, a new discovery of unique 3D tree fossils has opened a window into what the world was like when the planet’s early forests began to develop, expanding our understanding of tree architecture throughout Earth’s history.
Five fossils of trees buried alive by an earthquake 350 million years ago have been found in a quarry in the Canadian province of New Brunswick, according to a study published Friday in the journal Current Biology. The authors said that these new and unusual fossil trees not only bear a striking shape reminiscent of a Dr. Seuss drawing, but reveal clues about a period of life on Earth about which we know little.
“They are time capsules, little windows into landscapes and ecosystems deep in time,” said Robert Gastaldo, the paleontologist and sedimentologist who led the study.
Co-authors Olivia King and Matthew Stimson discovered the first ancient trees in 2017 while doing field work in a rock quarry in New Brunswick. One of the specimens they discovered is among the few instances in the entire plant fossil record — which spans more than 400 million years — in which a tree’s branches and crown leaves are still attached to its trunk.
Only a few tree fossils dating back to the oldest forests on Earth have been found, according to Gastaldo. Their discovery helps fill in some missing pieces of the incomplete fossil record.
“There are only five or six trees that we can document that, at least in the Paleolithic, have been preserved with their crown intact,” said Gastaldo, a geology professor at Colby College in Waterville, Maine.
He pointed out that most ancient tree specimens are relatively small, and are often discovered in the form of a fossilized trunk with a trunk or root system attached to it. His colleagues’ finding of a preserved tree that would have been 15 feet tall at maturity with a crown 18 feet in diameter left the paleontologist “amazed.”
Courtesy Tim Stonecipher
This model of the newly discovered Sanfordiacolis tree includes a simplified branching structure for easier visualization.
Researchers extracted the first fossil tree about seven years ago, but it took a few more years before four more specimens of the same plant were found in close proximity to each other. Dubbed “Sanfordiacaulis,” the newly identified species was named in honor of Laurie Sanford, the owner of the quarry where the trees were discovered.
The shapes taken by these previously unknown, 350-million-year-old plants look a bit like modern-day ferns or palms, according to the study, despite the fact that these tree species did not appear until 300 million years later. But while the tops of ferns or palms as we know them are characterized by a few leaves, the most complete specimen from the newly discovered fossils contains more than 250 preserved leaves around its stem, with each partially preserved leaf extending about 5.7 feet (1.7 metres).
This fossil is encased in a sandstone boulder about the size of a small car, according to Stimson, assistant curator of geology and paleontology at the New Brunswick Museum.
He said the unique fossilization of the group of trees was likely due to a “catastrophic” landslide caused by an earthquake that occurred in an ancient lake.
“These trees were alive when the earthquake happened. They were buried very quickly, very quickly after that, at the bottom of the lake, and then the lake went back to normal,” Stimson said.
Finding complete fossil trees is rare and much less common than finding a complete dinosaur, according to Peter Wilf, a professor of earth sciences and paleobotanist at Pennsylvania State University who was not involved in the study. Wilf noted via email that the “unusual” new fossil tree was a remnant of a time period when there were almost no tree fossils.
“The new fossils are a milestone in our understanding of how early forest structure evolved, eventually leading to the complex rainforest structures that support most of Earth’s living biodiversity,” Wilf added.
To King, a research associate at the New Brunswick Museum who found the fossil collection, Sanfordiacolis would have looked like something taken straight from Dr. Seuss’s most popular works.
“Did you know in the movie ‘The Lorax’ that trees have big balls at the top and narrow trunks? These structures probably have a similar structure. You have this huge crown at the top, and then it narrows and sticks to this very small trunk,” King said. Totally Dr. Seuss-esque look. “It’s a weird, wonderful idea of what this thing could look like.”
But the reign of Sanfordiacolis The researchers said this did not last long. “We’re not seeing this plant structure again,” Stimson told CNN. He noted that it grew in the Early Carboniferous, a time period at the end of the Paleozoic era when plants and animals were diversifying as they began to make their way from water to land.
Most evolution is experimental, and success is often measured by the diversity of a species, or its ability to adapt to many different places and conditions. Stimson added that the strange collection of tree fossils provides evidence of a “failed experiment of science and evolution.” “We’re really starting to paint that picture of what life was like 350 million years ago.”
Courtesy Matthew Stimson
Researchers excavated the first fossil tree of Sanfordiacolis about seven years ago, but four more specimens were found in close proximity to each other a few years later.
Fossils like Sanfordiacolis are not only useful in helping humans understand how life changed in the past, they can help scientists figure out where life on our planet might be headed next.
The presence of this particular species indicates that trees in that period began to occupy different ecological niches beyond what was previously understood, according to the researchers behind its discovery.
Gastaldo sees this as an indication that plants – like many early invertebrates – were experimenting with how to adapt to the environment. The earthquake, which likely petrified trees, also provides new geological evidence of what might be happening in Earth’s systems at the same moment in time.
“This is actually the first evidence we have of the existence of a ‘tree’ between what grows on the ground and what can rise above the ground,” Gastaldo said. “What was there?”