This morning I awoke to see the Gingko (Ginkgo biloba) shedding it’s fan-shaped leaves. First I noticed the golden carpet ringing the tree trunk, and then I headed out and stood underneath the boughs to hear the last tumbling gingko leaves.
Gingko Leaves Retrospective
Here’s what I wrote on November 3, 2010 on my blog when the gingko leaves let go and I first photographed the peculiar phenomenon.
Each autumn the leaves of an enormous old Ginkgo Biloba tree in our yard retain their leaves until the frigid end. They’re among the last leaves to fall, and they remain green until just a day or two before cascading down. And when they decide it’s time to let go, they all do it at once.
An enormous canopy of a tree reaching about 100 feet tall covered in thick foliage one day and naked the next. It’s dramatic. And slightly surreal. (virtualDavis)
Gingko Leaves 2012
The gingko leaves had transformed from green to brilliant golden in the last few days, so I have been anticipating their fall, but the change is so stark and so sudden each year that I can’t help but stop and wonder about this mysterious tree “with no close living relatives… similar to fossils dating back 270 million years.”
During autumn, the leaves turn a bright yellow, then fall, sometimes within a short space of time (one to 15 days). (Wikipedia)
But why? Why (and how) does this prehistoric species retain its chlorophyll-rich leaves so much later than other deciduous trees? And why do they drop so suddenly, so precisely — the entire vast canopy shed in a matter of hours — after a deep frost?
If it were the first hard frost or the most severe frost to date, it would make sense. But last night was neither. And yet almost all of the leaves have cascaded down to the ground over the last few hours.
Gingko Leaves Mystery
Can you explain the gingko leaves dramatic behavior? Please post your hypothesis (or scientific solution to this mystery) in the comments below. Thanks.