Archives for posts with tag: summer solstice

Trees are a treasure, a joy to have around.  They provide a habitat for birds, insects and other critters; act as a buffer against wind, rain and snow; and are the main generator of atmospheric oxygen and consumer of carbon dioxide.  Plus, they are beautiful to behold.  If they are not the focus of a picturesque view, they are probably framing it.

But sometimes they get in the way.  Usually, this is merely an annoyance, such as when they block the view (see, for example, August 12, 2013).  Other times, though, trees can block solar exposure, often to detrimental effect.  I’ve become painfully aware of this phenomenon in the garden as the summer has wound down.

I noticed this morning, for instance, that the garden is still in the shade long after 8:00 am, the hour at which it came into full sun at summer’s peak.  Two months after the summer solstice, however, the sun is already quite a bit lower in the sky and as a result, the tall trees to the east of us are obstructing its direct rays.  It is light in the early morning but it is not exactly sunny.

Similarly, this afternoon, the tips of the fir trees on our neighbor’s property, just to the southern side of our pool fence, are casting a shadow on the south wall of the planters.  The inclination of the sun will only get lower as the days pass while the trees will only get taller with each passing year.  Soon, the shadows will pass across the vegetables shortly after midday, further shortening the growing day.

This is in spite of the fact that we removed two large trees in the spring (see May 17, 2013 and May 17, 2013, part 3).  Their absence has made a huge difference in the garden’s afternoon sun exposure but as it turns out, the impact’s duration is limited to the period starting a month before the solstice until a month afterwards.  Outside of that two-month range, we will feel the effects of the changes in solar exposure in the house more than in the garden.

Which brings us around to the beneficial aspects of solar shielding (to end on a positive note, lest anyone think that I am hostile to trees).  In warm climates, properly placed trees prevent solar gain within buildings and reduce their cooling load.  Where the weather is warm the year round, evergreen trees maintain a constant screen.  Alternately, where winters are cold, deciduous trees conveniently drop their leaves, allowing solar radiation to pass and provide natural heating.

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It has formally been summer since last Friday (June 21) but if I had to base my assessment of the season solely on the weather, I’m not sure I’d agree that it is summer.  With the exception of a few days at the beginning of the month, it has been as cool as it was back in April and May.  And then there’s the rain:  Almost five inches so far this month.

Weather aside, not everyone would agree that summer started on the summer solstice, especially those living in the southern hemisphere where the seasons are the opposite of ours on the north half of the planet.  I was reminded of this by a recent post (from Australia) by BetR2 (see “Am I Learning or Just Confused??? When is the first day of the season again?”).  For her, the start of winter was the source of her confusion.  It seems that there is no consensus as to what officially starts (or ends) a season.

Growing up, I was taught that summer occurred during June, July and August; fall spanned September, October and November; the winter months included December, January and February; leaving March, April and May for spring (although spring almost never lasts three months, even in the northeast US!).  BetR2 was similarly instructed, it appears, although of course, the seasons—and not the calendar—are reversed where she lives.

Others (such as the folks at Google) base the seasons on the astronomical milestones:  the summer and winter solstices and the autumnal and vernal equinoxes.  Followers of this philosophy tend to be staunch despite the irony that summer begins with the days getting shorter and winter with the days getting longer.  I think there is some meteorological basis for this, however, due to heat lag.  In summer, the nights are not long enough for the day’s heat to dissipate and as a result, it continues to accumulate after the shortest night occurs.  The temperature gets hotter even as the days grow shorter.  Eventually, though, the conditions reverse and we start heading back towards cooler days and, eventually, winter.

Another practical approach is to use holidays as the demarcation points.  In the US for example, summer “officially” begins with Memorial Day (the last Monday in May) and ends on Labor Day (the first Monday in September).  Christmas often considered a good time for winter to start (although some would argue for Black Friday, which follows Thanksgiving and opens the holiday shopping season).  To round out the seasons, Easter makes a nice transition from winter to spring, with its obvious connotations of rebirth.  Naturally, there are strong cultural, ethnic, and religious influences on this practice.

However defined, it is now summer (in the northern hemisphere) by any calendar.  All we need now is for Mother Nature to catch up.