(March, 2014) We moved into our new house in the fall of 1989, and began landscaping the yard as early as possible the next spring. We wanted color, so we planted two flowering plum trees in front of the house. They lived up to their billing as far as color was concerned; they
produced clouds of pink blossoms early each spring, and highlighted the area with purple leaves through the following summers. But the old saying, "Nobody’s perfect," applies to trees as well as people; they proved to be incurably shallow-rooted, and both blew over when the March winds arrived the next year. At that time they were still small enough to lift, so I straightened
them up and supported them with guy-wires; but as they grew they began to lean again, eventually pulling the wires out of the ground. Each year thereafter, as they got bigger I tried to move their center of gravity back to the mid-point by pruning off branches on the leeward side; but it was a losing battle. The pruning made the remaining branches on that side grow faster, and
I knew their days were numbered. So I was not surprised when one of them fell over in an ice storm last month.
During the night the freezing rain had coated each twig on the tree with about a quarter of an inch of ice. It had then changed to snow, which was still falling when I got up, so there was nothing to do except sit at the kitchen table and think about it. Naturally, I began to wonder how much weight it took to bring down the tree. Collecting the
information to make such a calculation was simple enough: I brought in the tin can that serves as my rain gauge in winter and warmed it; the ice and snow it contained converted into about an inch of water. The branches of the tree extended about ten feet on each side of the trunk, and the formula for the area of a circle has not changed since I learned it in the fourth grade.
The weight of a cubic foot of water (62.4 lb.) was easy to look up. Doing the calculations there at the table took longer than I expected… I can’t remember the last time I did long division by hand… but eventually it came out that the water required to cover a 20-foot circle one inch deep would weigh 1,634 pounds. If half of that water stuck to the tree as ice, it would amount
to about 800 pounds.
Looking at that number on the scrap of paper, it was hard to visualize what 800 pounds of ice would look like. My wife, who usually doesn’t show much interest in mathematical problems, suggested that maybe a partridge had flown into the tree; but on reflection, she realized that an 800-pound partridge defied even her imagination, and besides, they never
go into plum trees. However, everyone has heard the old joke about the 800-pound gorilla, and it was not long before the image of a gorilla sitting in the plum tree popped into my mind. It was an intriguing idea, so I went out to look for signs of it. I found the tracks of a dog, a couple of cats, and an indeterminate number of rabbits, but there were no gorilla tracks in
sight. At that point, I realized that I really don’t know much about gorillas… the image I had in mind was King Kong hanging to the top of the Empire State Building with Fay Wray in one hand and swatting at a passing biplane with the other. Being a biologist for 60 years has taught me not to take things for granted. So I went to "Google" on my computer and typed in my question:
"How much does an 800-pound gorilla weigh?" As I had suspected, the computer had no sense of humor and took the question literally. It sent me to a whole screen full of articles that explained the origin of the joke, and it also informed me that the heaviest gorilla ever recorded was an old male that weighed about 600 pounds. He lived in a zoo where there were no females to
chase and no territories to defend, so he had nothing to do but sit around and eat. In the wild, male gorillas rarely reach 500 pounds, and females, a couple hundred less.
It had been rather exciting to imagine the expression on the face of an 800-pound gorilla when the tree he was in collapsed, so it was something of a let-down to learn that such a creature didn’t exist. It was even more depressing to realize that when it came to practical examples, I had no real experience that would allow me to visualize whether the
weight of even a teen-age female gorilla would tip the tree over. So I was stumped for a while, until a down-home example came to mind. When I was a teen-ager, it was a day to be proud of when a boy was able to carry a 100-pound sack of feed from the pickup truck to the barn. I suppose I was probably 12 or 13 years old when I made that rite of passage, and after that it became
a regular chore, so I have a pretty clear idea of what 100 pounds of cow feed looks like. Thus it was easy to visualize various numbers of feed-sacks perched in strategic positions in the tree, and although they didn’t have the lasting visual impact that gorillas would have, I was convinced that no more than 200 pounds of either cow feed, gorillas or ice would have been
sufficient to bring it down.
My wife was not thrilled by the prospect of having a fallen tree in front of the house for the rest of the winter, but I was able to convince her that wood gets harder when it is cold, and my chain-saw is balky even in warm weather, so surely it would not be possible to remove the tree when noon-day temperatures are below freezing. So the tree is still
lying there; and as weeks have passed, she has become rather intrigued by it. The small birds that patronize the nearby feeder use the fallen tree for shelter whenever a marauding cat comes by, and the drama is easily visible from her chair by the window while she has her morning coffee. It has actually been educational; she has added house finches to the list of species she
can recognize (the other species on the list is the cardinal), and she was quite excited the other day when a hawk swooped down and snatched a sparrow from a twig while she was watching… a practical example of the nearness of the food chain. She may yet become an ecologist.
As I write this, there is still a foot of snow on the ground, but time is drifting by, and the equinox will be here in less that a month. Days are getting longer, and I have already seen a bluebird and two robins in the yard. A great horned owl was hooting in the Great Forest behind our house last week; its mate is already sitting on her eggs, and by the
time they hatch perhaps the snow will be melted, exposing the tunnels where field mice have been breeding all winter. The food chain will go on; and believe it or not, spring will come. We ecologists know these things. Trust me.
Read other articles by Bill Meredith