Mystery of the Ginkgo

My parents have a beautiful ginkgo tree outside their back door, and growing up, it was always sort of a contest to predict when its leaves would fall.  If you aren't familiar with gingkos, they truly do experience a leaf exodus as Nemerov describes in his poem below.  One day, every leaf is clinging to its branch, and the next, nearly all have hit the dirt.

"The Consent" so beautifully describes that process but also makes us wonder how swift and complete it could be for humanity.  Could it?

The Consent

Howard Nemerov

Late in November, on a single night
Not even near to freezing, the ginkgo trees
That stand along the walk drop all their leaves
In one consent, and neither to rain nor to wind
But as though to time alone: the golden and green
Leaves litter the lawn today, that yesterday
Had spread aloft their fluttering fans of light.

What signal from the stars? What senses took it in?
What in those wooden motives so decided
To strike their leaves, to down their leaves,
Rebellion or surrender?  And if this
Can happen thus, what race shall be exempt?
What use to learn the lessons taught by time.
If a star at any time may tell us: Now.