Nature Art: On the Sidewalk
From Boston to Berkeley, leaves are falling, have fallen, become compost. Fresh concrete sidewalks keep the images of leaves around a bit longer as concrete prints and the ethereal tannin print.
Tannin prints, with their lovely sepia tones, show up best on light=colored sidewalks, like this one in Berkeley. Though the chlorophyll is absorbed back into the tree before leaves fall, the tannins are not. Winter rains have washed tannins out of the fallen leaves of this Japanese maple. Oak leaves contain the most tannins of common tree species, but we rarely see prints from the oak because its thick leaves break down over many seasons; they are unlikely to lie on the same spot on the sidewalk for all that time. Animals, bacteria and fungi avoid leaves and unripe fruit with high concentrations of tannins. In the case of animals, they are likely avoiding the astringent taste. Unripe quinces and persimmons are particularly high in these protective tannins.
We taste the astringency of tannins in unripe fruit and when we drink black tea or drink red wine--it is that almost bitter, puckery sensation you enjoy on your tongue. If you're like me, though, you modify your tannins by adding milk to your tea. Harold McGee, author of the cooking reference "On Food and Cooking," says, "The sensation of astringency is caused by the ‘tanning’ of the proteins in the saliva and mucous membranes of the mouth; lubrication is reduced and the surface tissues actually contract."
Concrete prints have no chemistry behind them: leaves fall, cement is wet, their weight makes a print. They show up best in early morning or late afternoon when slanting light catches the edges of their silhouettes on a sidewalk. Here is one from a Boston sidewalk:
This one, because of the light, looks as if it is emerging from the concrete, but it isn't:
Once you start looking down at sidewalks, it is hard to stop. Even footprints start to look interesting! Just think of Hollywood and the movie star prints at Grauman's Chinese Theater...
-- Sue Fierston paints and teaches just outside of Washington, D.C. in the Chesapeake Bay watershed. As a painter, she works in acrylics and watercolor and is in the middle of a series called "100 Flowers." As a teaching artist, she works with teachers to bring art into their classrooms in grades 4-8. Her posts focus on her nature-themed art collaborations. For a look at her paintings or more about her teaching, check out her website at suzannefierston.com.