Thursday, October 17, 2024

GINKO: THE MAIDENHAIR TREE

Living and Fossil Ginko biloba
The gorgeous yellow lobed leaf you see here is from a Maidenhair Tree — Ginko. These lovelies grow slowly but are well worth the effort with their delicate and distinctive lobed leaves of green and yellow. 

Ginko are Living Fossils native to China. We find them in the fossil record as far back as the Permian, 270 million years, rising with cycads, seed ferns and early conifers. They were part of the low, open, shrubby canopy covering our world well before the first flowering plants arrived. 

Ginko grew when Weigeltisaurus jaekeli, the oldest gliding vertebrates first soared our ancient skies and the first wee beetles munched on decaying wood on our forest floors. It is the long history of predation by beetles and their friends that have made Ginko what they are today — hardy, stinky and weaponized. 

These trees are truly a wonder. Consider that they have lasted since the Permian, living through multiple extinction events that wiped out millions of species on the planet. They are one of the few living things to survive a recent human-made extinction event — the atomic bomb blast in Hiroshima, Japan on August 6, 1945 — weathering one of the most horrifying moments in human history. 

170 Ginko Survived the Atomic Bombing of Hiroshima
When the bomb dropped on Hiroshima it created a fireball that bloomed 1,200 feet in diameter, vaporizing most everything in its radius. 

Somehow 170 resident Gingko trees withstood the ferocity and heat of that blast — and they are still standing to this day, 76 years later. Seemingly impossible, and yet quite true. It is because of their hardy nature that we began looking closely at their genetic make-up. 

Plants with seeds are either angiosperms, our showy flowering plants, or gymnosperms, the naked seed plants. Ginkgo are gymnosperms but in their own subclass, Ginkgoidae. The ginkgos we see growing today are the last remaining member of that subclass.

We see Ginko's rise and diversify in the Permian. By the Jurassic, they had spread across Laurasia, the lands that would become modern Asia. It is this lucky foothold in a young Asia that would eventually save their species. 

From the Jurassic to the Pleistocene their numbers slowly dwindled. We have some great Eocene fossils from outcrops at Quilchena, Tranquille and the McAbee Fossil Beds that show them doing quite well in the interior of British Columbia some 50 million years ago, but this pocket of lush growth seems the exception and not the norm. 

By the Pleistocene, just 2.5 million years ago, glaciation threatened to kill off the last of the ginkgo lineages. Their last stand and platform for global distribution once again was rooted in the forests of central China. Every Ginko you see today originated from that small foothold in China. 

While beautiful, Ginkgo are stinky. I was out for a late stroll the night before last to try and catch a glimpse of the Aurora Borealis up at Queen Elizabeth Park. As I walked along one of the darkened pathways, my nose caught a whiff of something smelly. Think vomit mixed with decaying leaf matter. I looked up to confirm the culprit, a gorgeous bright yellow Ginko backlit from above. 

Ginko in Dan & Lena Bowen's Garden
The reason for their terrible smell is quite clever. It is the result of the chemicals they produce to ward off insects, fungi and bacteria. 

Ginko boast a massive genome comprising some 10.6 billion DNA letters within each strand. You and I boast only three billion letters in our human genome.

Written within this vast genetic code are 41,840 genes or templates that the tree’s cells use to make complex protein molecules that build and maintain each tree and give these stinky lovelies an enviable anti-insect arsenal. 

The photo at the top shows the yellow lobed leaves of a Ginko biloba against an Eocene partial lobe from the McAbee Fossil Beds up near Cache Creek, British Columbia, Canada. The bright yellow is this tree's Autumn colour palette. The bright green leaves you see in the bottom photo are the summer colour palette of this same species. The photo was taken in the summer in Dan and Lena Bowen's garden during the VIPS Saber-toothed Salmon Barbeque. This year, Dan-the-Man is saving some of those lovely lobed leaves to make up some tea from one of the oldest living species in the world. I am excited to give it a try.