Leaf Abscissions

Many of the trees here in eastern Iowa have continued to hold their leaves this year. It is a little later in the year than normal. Last night, the temperature got to 26˚F which prompted a phenomenon called abscission. This morning in the warm sunshine, the leaves started dropping quickly. We’ve watched this occur each fall for many years as cold weather approaches.

I have an app on my iPad called NightCap Camera. It is normally used for low-light and night sky photography. One setting is for lines left by moving objects. The iPad is set to be stationary while the exposure takes place. It captures sequential images recording locations of objects that moved during the exposure. It works in the dark or daylight. This first image was about 20 sec. Exposures of 1/288 sec were recorded as the leaves dropped.

NightCap Light Trails mode, 19.46 second exposure, 1/288s shutter speed.

Here is a second image lasting about 2 minutes. This a visual definition of fall.

NightCap Light Trails mode, 113.78 second exposure, 1/273s shutter speed.

11 thoughts on “Leaf Abscissions

  1. joynealkidney

    I’m fascinated by how ash trees decide to drop their leaves in just a day or so. And those wonderfully “leathery” gingko leaves that carpet a goodly area. Love crispy leaves skittering on the porch. My mother might have called it “slovenly” not to have a swept porch, early, but I enjoy seeing them there. I’m hopeless in autumn.

    1. Jim R Post author

      I understand. I walked to the precinct voting location this morning and took the trees route on purpose just to see them shed. Some are very reluctant, tho.

  2. Jan

    I love the photos. The trees appear to be saying, “OK, let’s just get this finished!” And I can echo the rapid drop of ash tree leaves. Ours are leafless this morning.

  3. BJ

    New word & knowledge for my vocabulary-abscission – thanks for the education. The photos are just [old school term] COOL!

  4. shoreacres

    Sometimes our bald cypress will do that synchronized leaf drop, too. I remember years when I left for work and every tree was fullly leaved. When I came home for lunch, there wasn’t a leaf left on the trees: just a circular pile of pretty rust underneath each one of them.

    1. Jim R Post author

      On my walk to vote this morning, I passed trees that were bare, some with falling leaves, and some still green. I think they won’t last long tho.


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