Everybody knows that when it’s hot, it’s hotter in the sun than in the shade. And when you’re riding a bike on city streets during a heat wave, streets with huge trees are more pleasant to ride than those without.
During last week’s warm spell I thought I would try for some data to back up the conventional wisdom. So I packed a household thermometer on my ride on Friday afternoon.
The results were less than spectacular. There was a difference in ambient temperature all right, a temperature difference between sunny blocks and blocks shaded by an ample canopy of leaves above. But the difference was not great, not as great as I had hoped.
Still, in the middle of a summer’s day lots of big trees have an obvious cooling effect on the people below them. We can feel the difference even if the difference in Fahrenheit is just a few degrees.
Which is one reason Albany and other towns try to protect mature trees and require new ones to be planted when new parts of town are developed. But this protection is not strong.
Big old trees are cut down all the time when they’re in the way of a new street or housing development. Or if they threaten to break up sidewalks or pavement. Or because they cause too much work when they drop a million leaves in the fall.
New trees planted in their place don’t achieve the desired result — scenic enhancement and summertime cooling — for 20 or 30 years. And some never do because they are what you might call “mall trees,” slender and small, with no chance of growing into something that resembles a 50-year -old maple or majestic old oak.
I don’t know what could be done to provide greater protection for big shade trees in the city. But if it’s true that we are likely to face longer and more severe heat waves in the summers to come, we ought to make sure to save as much of the tree canopy as we can. (hh)