BY JILLY MacDOWELL | Between McKean Street and West Passyunk, 24th Street splits into a boulevard. The two-block median between Jackson and Wolf is lined with fifty-foot London plane trees. These "city trees," bred accidentally from two kinds of sycamores in the mid-17th century, are so nicknamed for their pollution tolerance, root compaction and shade canopy.

London planes get their name from their ubiquity in the British capital in the Victorian era. These trees subsequently became popular in Paris, and New York, and Philly because of its desire to imitate those cities. The trees lining the Ben Franklin Parkway, as Philly's own Champs Elysées, are London planes.

In a discussion about urban tree uniformity versus diversity on the Urban Wildlife Podcast, research ecologist Lara Roman advocates for the "aesthetic value of monocultures on a particular block" and the "cathedral effect" of these rows of trees, more dramatically evident on the 24th Street than on the Parkway.

The treetops have expanded unfettered on this median in Point Breeze, enhancing the cathedral effect. They'll likely grow, vertically, another 20-30 feet. It's the London plane's signature camouflage bark, what we see at street level, that's most recognizable and as ubiquitous in the city as redbrick. As lovingly depicted by the late, great Philly Trees blog: "Catching the colors of [its] painted bark, each layer a different color, its constant exfoliation is the very reason [it] makes such a stout and healthy street tree." Why it exfoliates is unknown; theories include to rid itself of soot and other pollutants, to protect again invasions by parasites and fungi, and/or because the tree's photosynthesis may take place in the tree's cortex, just below the bark. In so doing it endures the harshness of urban living.

This little quadrangle is quiet this time of year since nearby charter school Universal Vare isn't in session. There's very little traffic, and nary a sound but the low rumble of the elevated freight train or the occasional celebration on the court at Smith Playground. Benches, one on each block, await.

The #Yoasis is a series of posts on this site that seek to inform the reader of places in an increasingly bustling where one may encounter a sense of calm and tranquility. Philadelphia is full of Places We Can’t Understand, and we have written about those, too; as a counterpoint, a #yoasis is place in Philly that the body and spirit understands intuitively, and feels at peace. If you’ve got a #yoasis you feel comfortable sharing with us, please do by emailing us at tips[at]philebrity[dot]com.