Friday, June 6, 2014

Again, Trees

Trees are wondrous things, and I often take them for granted. Caught up in my daily preoccupations, I often rush by them without giving them a second glance, focused as I am on matters at hand, most of which, truth be known, I can't do very much about.

I often drive along with my left arm hanging out the open car window, and I have acquired quite a prominent farmer's tan that way. It's particularly dark this year, considering all the rambling I've done in search of fodder for this column and the photos to accompany them. One day, oblivious to the sun's intensity, and forgetting the weather forecaster's warning that the ultraviolet factor was dangerously high that day, the tender skin on my arm just above the elbow was burned and required several applications of that blessedly soothing concoction known as aloe gel. Despite my sunburn, it was along one stretch of Route 5 in Saco that I was reminded that afternoon of what a blessing trees are, especially on hot cloudless days.

From the intersection of routes 5 and 35 in Dayton to the Waterboro town line several miles west, the woods alternately deepen and thin on either side of the road. My arm becomes a sensing device of sorts as it picks up the changes in temperature that occur between the wooded areas and sections where the tree line is farther back from the road and more open sky appears. Along one particularly dense wooded stretch, the temperature dropped by a good 10 degrees, and my arm was actually chilled. Then, when the tree canopy opened up again to allow the sun through, it got decidedly warmer. I tested the theory all the way to Waterboro where the road widens and the trees no longer join together closely enough over the road to alter the temperature until the turnoff to Shaker Hill on route 202 in Alfred.

The coolness that trees impart is due to several factors beyond their ability to provide us with shade. Trees are natural air conditioners that operate exclusively on solar power to chill the air around us and keep it chilled for long periods of time. This is where water, good old H-Two-0, comes into play, much as it does inside an electrically-powered air conditioner. Trees take in hundreds of gallons of water from the soil each day through their roots. This water travels to every part of the tree to keep it hydrated and to assist with the production of food in that amazing process known as photosynthesis.

Water molecules are composed of hydrogen and oxygen. In a complex process, the sun stimulates the hydrogen molecules that are utilized during the food production process, while the oxygen is given off through the leaves. Any excess water not used during the production of the sugars necessary to a tree's survival is also released in yet another process known as transpiration, which closely resembles what we call perspiration, or the process by which our own bodies produce water, or sweat, to keep us cool. So not only do trees intercept the sun's damaging rays, they also keep us cool with the water they release into the air around them. This cooling ability increases exponentially depending upon the number of trees in any given area. Thus, the denser the forest, the chillier it will be, because the air around and between the trees is saturated with cool water.

Trees also do not retain heat in the general sense. Thus, once the sun sets, they and the air around them cool almost immediately as opposed to the asphalt and concrete that weave their way through cities and towns and that store the heat long after sundown. This is a welcome effect during the winter, but it quickly becomes the bane of city dwellers during the hottest times of the year, especially in places where there is little or no vegetation.

The next time you are out of an evening, notice how much cooler it is in the more wooded areas as opposed to the city streets. Take note of the decided chill in the air in places where the treetops join hands, if you will, to do what they were designed to do which is to naturally and efficiently keep us cool and refreshed and all without our having to flip a single switch.

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