Nova Scotia can lay claim to the oldest known pine tree fossils, which date back to the time of the dinosaurs.

The fossils, which measure between seven and 20 millimetres and are approximately 140 million years old, were discovered in a gypsum quarry near Windsor that is operated by Fundy Gypsum.

Paleontologist Howard Falcon-Lang of Royal Holloway University of London discovered the fossils in Nova Scotia and brought some back to his office in the U.K. The fossils sat for five years while Falcon-Long worked on other projects. 

Generally a 'laborious' process

"I'm a bit ashamed now that they were stuck there all that time," he said in a telephone interview Wednesday. "If I had known just how exciting the material was, of course I would have given it a much higher priority."

Once he got back to the fossils, he used an acid solution to dissolve the gypsum and discovered the fire-charred pine twigs after putting the pieces under a scanning electron microscope.

"When you try to determine what a fossil is, it's generally not a eureka moment, where you look at it and you know what it is. Generally it takes a long laborious process," said Falcon-Lang. 

Ancestor of the modern pine

Falcon-Lang said the fossils, known as Pinus mundayi, are the ancestor of modern pines and may help show why today's tree is so well adapted to fire. 

"They have a range of plant traits that allow them to do actually very well when fires burn through," he said. "It's been a great question among ecologists, why have pines adapted to fire?

"Well these earliest pine fossils that we found, 140 million years old, we know evolved at a time when there was more oxygen in the atmosphere. When there's more oxygen of course there's more fires and those fires are more catastrophic and widespread."

Previous discoveries 5-10 million years younger

Falcon-Lang hypothesizes pine tree forests can recover so quickly after a fire possibly because their ancient ancestors evolved in such a fire-prone environment. 

Andrew Hebda of the Nova Scotia Museum of Natural History says the fire that blackened the fossils was likely caused by a lightning strike. Such strikes often burned large tracts of land.

"They would burn away slowly leaving all of the carbon, leaving all of the structures in there without getting shifted down to a little pile of grey ash," Hebda said.

​Hebda said Falcon-Lang was working with Martin Gibling at Dalhousie University when he found the fossils.

Prior to this discovery, the oldest pine species encountered was about five to 10 million years younger, said Falcon-Lang.