Researchers have found fossils indicating that the existence of the pine tree, a defining feature of many landscapes through the Northern Hemisphere, can be dated back at least 140 million years to the Cretaceous period- back in the Age of the Dinosaurs.
A research team from the Department of Earth Sciences at Royal Holloway, University of London discovered the fossils in the form of charcoal, the result of a prehistoric wildfire, in a gypsum quarry in the Canadian province of Nova Scotia. The charred twig is less than a quarter-inch long, but up close, the divots, where pine needles once sprouted, can be viewed. An analysis of the twig's internal material has also located the resin ducts through which sap would have once flowed.
The findings highlight that that pine trees co-evolved with fire during a period when oxygen levels in the atmosphere were much higher than today and that forests were especially inflammable.
"Pines are well adapted to fire today. The fossils show that wildfires raged through the earliest pine forests and probably shaped the evolution of this important tree," study co-author Dr. Howard Falcon-Lang outlined.
He also explained that today's pine trees store a considerable amount of deadwood, which makes them burn more easily. At the same time, they also generate cones that only germinate after encountering fire, an evolutionary adaptation that ensures a new generation of trees is propagated.
Falcon-Lang described how the researchers processed rock samples in acid in order to expose the specimen. He said that he intends to return to the rock quarry in order to locate further pine samples as well as fossils of flowering plants that would have evolved around the same time as the ancient pines.
The fossils likely came from trees resembling the Scots Pine, which currently covers vast swaths of Eurasia. This specimen is at least 11 million years older than the oldest previously-discovered pine fossil.
Pine trees belong to the most widespread genus in the world, and scientists are avidly exploring their long process of evolution in order to gain more insight into their unique qualities of adaptation.
The findings were published in the March 7 issue of the journal Geology.
