City Creek Nature Notes – Salt Lake City

September 23, 2016

September 23rd

Contrasts in Color

5:30 p.m. Yesterday’s storm and cold continues through most of today, and it still rains during this afternoon’s jog. The storm is driven by a low pressure system that has stopped directly over Salt Lake City and the canyon. The clouds that soaked me last night have had time to travel around the circular storm track, and I feel same clouds that soaked me last night have returned for another try.

Some trees respond immediately to the rain and cold. River or water birches (Betula accidentalis H.) turn a bright yellow almost overnight. At the guardhouse gate at mile 0.0, the horsechestnut trees begin to turn. Their leaves become brown around the fringes and the color works towards the center of each leaf. The Gambel’s oaks have begun to turn in response to the cold. When they turn, the leaves go directly to a shriveled tan color.

The rain and diffused overcast light emphasizes the brightest color leaves, and the canyon is a study in color contrasts. The deepest red comes from western poison ivy (Toxicodendron rydbergii) and a chokecherry tree hidden behind a clump of Gambel’s oaks at picnic site 10. At that location, a sole Box Elder tree has also half turned, and with one-half green and one-half yellow leaves, the tree stands out with a bright light green hue. The brightest red-orange comes from a few select maples. A light blue and light purple are found in a few remaining roadside weeds, including some tansyasters. The brightest yellows come from two immature narrow leaf cottonwood trees and clumps of dried milkweed stalks. Most larger cottonwoods have not yet begun to turn.

It rains continuously through the night and into the half of the next day.

 

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