The Leaves That Didn't Fall

More intimidating than the dog that didn't bark.

We have four Japanese maple trees on our property, and there's this usual cycle they go through every November.  One day the leaves are in a muted red shade, as they have been all spring and summer.  Then, they suddenly turn a vibrant red a couple of days later, and soon after that the they quickly crumple and fall.  When the leaves on our Japanese maple trees started to change this fall, they didn't crumple; the only turned a pale grayish red.  I then waited for them to fall all at once, like they did before, so I could rake them.

And waited. And waited. And waited. And waited. And waited . . . until suddenly it was December.

It's December 7, and the leaves on our Japanese maples still haven't fallen.  (The picture above is of one of our trees, taken December 5.)  A friend of mine said that the warm autumn we've had up to now altered the transfer of water and sap to the cells in these trees that feed the leaf stems.  As the leaves lose photosynthesis and die off, a layer of cells connected to the leaf stems called the abscission layer is supposed to close off the flow of nutrients to the leaves, allowing the leaves to fall; when that doesn't happen and dead leaves stay on the trees, this is called marcescence.

Marcescence happens periodically in all sorts of trees, mainly oak trees, but I've never seen it occur in Japanese maple trees until this year. This is actually pretty scary - a species of tree not shedding its leaves as it's supposed to. There are two major disadvantages to marcescence.  One is that the dead foliage on a tree during the winter season causes the tree to use more water than it should have to.  The second, and far worse, disadvantage is that it can lead to great excessive damage to the leaves and/or branches in bad winters, because the snow can accumulate on the dead leaves and cause the limbs to fall from the limbs' failure to support the weight of the snow - exactly how so many tree limbs came down in my area during the October Surprise snowstorm of 2011.  Back then, many leaves on the trees were changing color but had not yet died.  But a tree limb full of dead foliage is no lighter than a tree limb that's still bearing leaves that are green or changing color along with leaves that have already died.

Okay, I'm worried.  I hope the abscission layers on these trees finally close off and let the leaves fall.  Maybe the cold - a cold snap is expected next week - will do it and then the leaves on or Japanese maples will tumble to the ground.  Fortunately, there's no major snowstorm in the foreseeable future as I type this - just a dusting.   But if they're still on the trees when it starts snowing big time, all bets are off.  Because this episode of marcescence, which I believe was indeed caused by a warm fall, isn't unique to our Japanese maples - other Japanese maples in my area still bear their dead leaves.  And while ours aren't impeding any electrical wires, others are.  Some of them are growing right into the wires.

And there are people in my Republican town who still don't believe in climate change.