City Creek Nature Notes – Salt Lake City

February 16, 2017

February 16th

Filed under: Astronomy, Common stonefly, Rock wren, Seasons — canopus56 @ 4:59 pm


2:00 p.m. A new front approaches from the southwest, and during this pre-spring, this means high winds and warm temperatures. February is unseasonably warm near sixty degrees, and at picnic site 11, where two weeks snow banks drifted to two or three feet deep, the snow is gone. The air smells more like late spring than the end of winter. Wildlife is slow to respond, but plants keep their own time. I hear a robin singing at Guardhouse Gate; the first since winter started. Three miniature stoneflies brave the road. Groups of lunchtime lawyers who run in the canyon usually beginning in late March are on the road. The buds on trees are not responding. They know snow may return again.

Because of the exceptionally warm February, I am feeling the disconnect between the astronomical seasons and natural rhythms. In the modern era, we define the seasons using astronomical waypoints (Sept. 20th), and in writing about the Wasatch Front Range in the 1950s, Barnes in his “The Natural History of the a Mountain Year” used astronomical seasons. But there are other definitions of the seasons. In writing about Concord in the 1850s in his “Journal”, Thoreau used traditional definitions of the seasons common the 1800s: spring began on February 1st and summer on May Day, or May 1st, and “Midsummer”, June 22nd, is our modern astronomical first day of summer. June 22nd was the “midsummer” referenced in Shakespeare’s play. These traditional definitions were more aligned with seasonal ecological changes, and there are six ecological seasons in temperate northern latitudes:

• Prevernal, March 1st to May 1st – in which temperatures have risen sufficiently to allow microorganisms to function and to resume their work of reducing the autumnal leaf litter. During this ecological season, early bulb plants sprout, often still surrounded by snow.

• Vernal, May 1st to June 15th – when the majority of plants regrow. Sometimes with is subdivided into the preestival, or “before summer”.

• Estival, June 15th to August 15th – summer, the time of greatest heat.

• Serotinal, August 15th to September 15th – when seeds are released in response to environmental triggers such as summer warming or summer fire.

• Autumnal, September 15th to November 1st – when leaf death and autumnal colors occur.

• Hibernal, November 1st to March 1st – winter, the time of greatest cold with freezing rain and snow.

These six ecological seasons feel more connected with commonplace perceptions of the seasons.

In Thoreau’s “Journal” on February 16th, 1852, he notes that the air is no longer crisp and clear as in early winter.

On February 16, 1900, an ex-Salt Lake councilperson made the case for increasing the City’s water supply by tunneling into the canyons, including City Creek, would be the lowest-cost method of developing new water supplies for the City. (Salt Lake Tribune).


November 21, 2016

November 21st

The Oaks put on Green Coats

Noon. It has been raining overnight and this morning, but the air remains warm. Usually, I associate moss on the trees with thick mats that adhere to the north sides of pines in the upper canyon beyond milepost 5.0. During the summer, except for stream side, there is not enough moisture in the air to support either moss or lichens. But the lower canyon today proves my impressions wrong. The sides of the trunks of Gambel’s oaks and horizontal branches have become soaked with snow melt and rain water. Trunks which had previously been a uniform grey, now are covered in the green of mosses and lichens. One some oaks, the lichen has a light green color that is luminescent against the dark tree trunk. Just beyond milepost 1.5, the interior of a copse of Gambel’s oak reveals, now that its leaves are gone, a large horizontal branch that is covered with thick mat of moss. The summer leaves provided a protected moist environment against the harsh mid-year sun. From along Bonneville drive up to mile 2.0, all of the Gambel’s oaks have come alive with green trunks.

At mile 0.4, a three inch long Leopard slug, also known as the Great grey slug, (Limax maximus) is slowly inches its way across the road. The last third of the grey body near the head is covered with large black blotches, hence the “leopard” name. This is another invasive species, originally from Europe. The rain has wetted the road, and this allows the slug to migrate across this summer barrier.

At Guardhouse Gate, today’s single insect, is a miniature unidentified spider hanging from the guardhouse’s community posting board. While picking up trash left from a beer party at Guardhouse Gate picnic area, I notice what appears to be a House wren (Troglodytes aedon) hiding at the base of a dogwood tree next to the stream. This identification must be wrong. The Rock wren is out of season and it is in the wrong habitat. At mile 1.1, a single Black-billed magpie hides in the center of an oak copse.

A bow-hunter walking up the road informs me that mule deer browse inside the Gambel’s oak copses for acorns. They do not eat the dry grass in the meadow, but they will graze on the green shoots at each grass clump’s base.

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