City Creek Nature Notes – Salt Lake City

April 11, 2017

April 10th

Time Limit

1:30 p.m. The canyon’s ridgeline retains a slight covering of snow, but it is heavier on Black Mountain and Scott’s Hill. The highest mountains on the Wasatch Front Range received two feet of new snow, but the gauge station at Louis Meadows has only a small uptick of one-inch in equivalent water precipitation, and this suggests at most two or three inches fell in upper City Creek Canyon. Some trees respond by covering the road with small broken twigs with leaves. Freezing overnight temperatures retain this snow, but the cool day is overwhelmed by the new bright sunlight of spring. Sunrise begins at six a.m. and sunset arrives at eight p.m., but it is the new height of the noon sun that gives spring its force. It is still unsuccessful at pushing back on winter’s control, but the tide turns in its favor. The noon-time light is simply so much more brighter than on vernal equinox almost three weeks ago. It almost hurts the eyes, and the intense light reminds that summer will eventually arrive. Under this light, what I had supposed was the over-wintering yellow fruit of the canyon’s ubiquitous poison ivy patches burst in small flowers. A single cultivar of purple grape hyacinth (Muscari armeniacum), which is common in the city, blossoms along the first mile road.

Yesterday, there was a large predator scat pile on the road. Predator wildlife scat is easily distinguished from the feces of domestic dogs that also frequent the road because predator scat is full of the fur of its mouse and squirrel prey. Predator scat also ends in a narrow tip, unlike the rounded ends of domestic dog scat. Given the size of the pile, it may have been deposited by a mountain lion. But today, as I leave the car at Guardhouse Gate parking lot, on the heavily traveled canyon road between Bonneville Drive and the lot, a coyote expertly bonds down a steep slope, crosses the stream, and bolts into the thicket on the far east side of the stream. Come to think of it, I have not seen two rock squirrels, first viewed in the parking lot about a week ago, for some days. From thickets on the side of the road, Black-billed magpies and other song birds are heard.

The coyote, rock squirrels, mice, and I share a common bond of all mammals as a result of our common genetic heritage. Our time in the canyon and on the Earth is limited by a pre-programmed number of heart beats: about one billion for most mammals and uniquely about 3 billion for humans. Like the canyon’s coyote, my time in the canyon a mortal limit. I only have at most 700,000,000 heart beats left to live and to see the canyon.

* * * *

In Thoreau’s “Journal” on April 10th, 1841, he remarks “How much virtue is there in simply seeing?” On April 10th, 1853, he notes that saxifrage is blooming.

* * * *

The hearts of mammals regardless of size beat between 1.29 and 0.17 billion times (mean: 0.73 +- 0.56) over their life (Levine 1997, Cook 2006). For humans, lifetime heart beats average about 3 billion (Cook). But adjusting for heart rate, body mass, and longevity, over a lifetime, the heart of a 2 gram mouse delivers the same amount of total oxygen per unit of mass as that of 100,000,000 gram blue whale (id). As the mass of mammals increase, their heart rate decreases and their longevity increases. The 2 gram mouse’s heart beats 500 times per minute, but the mouse only lives one year. A loin’s heart beats at about 50 times per minute, but it can live for sixty years. This well-defined log-linear relationship between resting heart rate and longevity varies systematically from the small (mouse, hamster, and rat) to the large mammals (horse, lion, and elephant), except for humans (id). Plotting the log of resting heart rate or metabolic energy per kilogram of mass against longevity for various mammals gives a nearly straight line (Atanasov 2007, Cook 2006), but the 3 billion beats of the human heart for 80 years of life sits as a distant outlier from the other mammals (Cook 2007). The 2 billion extra beats allotted humans, like our brains, sets us apart from other mammals. But for both humans and other mammals, the above suggests that at cellular level, there is a genetically pre-programmed length to all mammalian life.

It would wrong to conclude that human life can be extended by not exercising because the hearts of people who do not exercise will beat less. The relationship between a lower resting heart rate, general good health, and increasing longevity is well-known (Cook). For a person who does not exercise and has a resting heart rate of 90 beats per minute, their heart will beat about 3.8 billion times over eighty years. For a person who exercises for two hours per day at 110 beats per minute and who has a resting heart rate of 70, their heart will beat 3.1 billion times over eighty years, or about 80 percent of the effort of the non-exercising person. For high functioning athletes with resting heart rates of 50 beats per minute, their hearts will beat about 2.3 billion times in eighty years, or about 60 percent of the effort of the non-exercising person. For unknown reasons, ultra-fit humans, who have the lowest amount of body fat and the lowest body mass indices (BMI), have higher mortality rates similar to the obese and higher than the ordinarily fit of persons of normal weight (Lorenzini 2014). Lorenzini’s review should be read cautiously. Higher mortality of abnormally low-weight persons may be a cofounding artifact of terminally-ill patients losing weight as they expire. But the implications of exercise for not developing debilitating health problems after age 50 are self-evident, since the health of other organs depend on a healthy blood circulation provided by the heart. Among older men, exercise has a protective effect against developing cardio-vascular disease and thus, reduced general circulation and increased mortality (Kodama). This cardiac protective effect is known to be dose dependent amongst men with Type 2 diabetes (Church). More exercise provides more protection. This is only one physical benefit of several types of benefits from being actively connected to nature and the canyon.

* * * *

On April 10th, 2007, the AAA as part of its Great Battery Roundup program, pledges a $2 donation for City Creek Canyon Rehabilitation for every automobile battery delivered to the club (Salt Lake Tribune). On April 10th, 1927, Frank Robinson, a student from Coalville, won the annual marathon up City Creek Canyon (Salt Lake Telegram). On April 10th, 1916, L.D.S. Church members held a running race up City Creek Canyon. Non-Mormons, called “gentiles” by the Mormons, held a separate race along the East Bench (Salt Lake Telegram). On April 10, 1911, Water Commissioner Frank Matthews announced that dogs will not longer be allowed in City Creek Canyon unless they are kept on a leash because dogs have been swimming in the water supply (Salt Lake Telegram, Salt Lake Tribune, April 11, 1911). On April 6th, 1906, the Salt Lake Tribune reported that “streams of people” went up City Creek for recreation by horse carriage, on foot, and by bicycle (Salt Lake Tribune). On April 10th, 1898, the Utah Forestry Association and the City made plans for the experimental planting 300 ash trees in moist areas of City Creek Canyon (Salt Lake Tribune).


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