Autumn in Salt Lake City
Changing colors season of '09
The word 'autumn' has its roots in the French language but it was later normalized to the original Latin word autumnus. This season is a short interim between summer and winter, usually taking place at the start of the September equinox (Northern Hemisphere) when the sun is directly above the Ecuator on its zenith, for this reason days and nights both have the same duration.
With an average temperature in the low 70s for Salt Lake City, this is a good time of the year for outdoors activities without the summer heat. The gradual change in color on the leaves of some of the trees (deciduous:trees or shrubs that lose their leaves seasonally) creates spectacular displays that entice many people to grab their cameras, or painting canvas, and head out to neighboring parks, lakes, or hills to enjoy the sight. This time of the year is in fact so popular that Autumn is one of the top 100 names for girls in the United States.
What produces this change in color and why leaves end up falling?
During Fall the days are shorter and deciduous tress produce less clorophyll causing other colors on their leaves to stand out. Brighter colors of yellow, brown, orange, red, and purple are achieved when this type of foliage is exposed to a combiantion of less hours of light during the day and cooler temperatures at night.
The petiole is what holds the leaf attached to the plant, and it remains healthy as long as the plant keeps the correct level of the auxin hormone. When Autumn comes around the leaf produces less of this hormone, weakening the petiole and eventually causing the leaf to drop.
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