March 2, 2012
Ancient Forest In NY More Diverse Than Scientists Thought
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After unearthing a previously unknown portion of one of the planet´s earliest known forests, archeologists say the fossils of 385-million-year-old trees reveal a far more diverse ecosystem than researchers had previously thought existed.
Partially uncovered by quarry workers in 1870, the ancient forest beneath the tiny town of Gilboa, N.Y. has been of intense interest to paleobotanists since the 1920s.
Dating back to the Devonian Period, researchers early on recovered massive, bizarre looking trees that resembled modern-day palms with a crown of leaves and branches radiating upwards.
Now, however, a new construction project has uncovered a large, well-preserved tract of the forest.
“For the first time, we actually have a map of about 1,200 square meters (12,900 square feet) of a Devonian forest,” said Dr. Chris Berry, a paleobotanist at England´s Cardiff University.
“We know which plants were growing where in this forest, and how they were interacting.”
For years, researchers believed that the only species of tree in the ancient forest was the towering, palm-like Eospermatopteris, commonly known as the Gilboa tree.
It now seems, however, that the Gilboa tree shared the primitive sylvan landscape with at least two other tree varieties. One of these appears to have belonged to an extinct class of woody, spore-bearing plants known as progymnosperms. With creeping branches up to six inches in diameter, these massive plants once spread across the forest floor like a briar patch, sometimes reclining on and even climbing the Gilboa tree.
“Those trees were covered in little branches which sprung out in all directions and made a sort of thicket on the floor of the forest,” Berry told Live Science senior writer Stephanie Pappas.
The discovery of these specimens in particular, said Berry, was a “big surprise” considering that scientists have been studying the site for the better part of a century.
Researchers also recovered partial fossils of another tree belonging to a division of ancient plants known as Lycopodiophyta, or Lycopods, whose modern members trace their roots back some 410 million years. Lycopods are the oldest extant division of vascular plants on the planet and are distinguished by their rudimentary leaves that possess only a single column of vascular tissue.
The new Gilboa discoveries are causing researchers to reexamine their original conjectures about the nature of the forest. While most previous researchers believed it to be part of a massive swampland, Berry and his co-researcher William Stein of New York´s Binghamton University now suspect that the wooded landscape may have stood upon the a flat shoreline of a long-vanished coastal plain.
“I´ve spent 20 years trying to imagine what these plants were like as individuals, and yet I really had no conception of them as an ecosystem,” said Berry.
“Going to Gilboa and sitting in the middle of the forest floor, you could almost see them growing out of the ground. “¦ The fossil forest came to life in front of my eyes in a way that has never happened before.”
This newly discovered complexity in early forest ecosystems is likely to have a ripple effect across the entire science of paleobotany and, indeed, all branches of biological history.
As Berry noted, the appearance of terrestrial forests some 400 million years ago radically altered ecosystems across the planet. For instance, prior to the Devonion Period — when clusters of large trees began bursting onto the scene and the large-scale conversion of atmospheric carbon dioxide into organic matter took off in earnest — carbon dioxide levels were as much as 15 times higher than current levels.
According to Berry, the Gilboa discoveries are starting to paint for researchers a more complete, nuanced picture of how exactly such processes took place.
“We´ve gone from knowing about plants to knowing about a forest. “¦ That´s really been the breakthrough for me,” he added.
A report of Berry and Stein´s research was published Wednesday in the journal Nature.
Image Caption: Working in conjunction with William Stein at Binghamton University, Frank Mannolini of the New York State Museum developed a sketch of what the Gilboa forest site might have looked like about 385 million years ago. Credit: Frank Mannolini, New York State Museum
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