Once, while out on a country walk, some people I met along the road asked me directions to a particular local temple.
“Just go straight down this road,” I told them. “Then turn right just before you come to a big hackberry tree.”
These directions seemed perfectly clear to me, but the people still appeared a bit confused. With no particular destination in mind anyway, I decided to just take them to the temple. We walked along the road and then started to turn right. “Ah, so that’s a hackberry tree,” said one of them. At that point I realized my mistake. I’d foolishly assumed that they would instantly know a hackberry tree when they saw one.
“But how do you know it’s a hackberry?” asked another. I started to answer, and then stopped. How did I know it was a hackberry? Well, for one, the wide spreading branches were very typical of a hackberry, and hackberries are often planted at crossroads for their superior shade value. But then cherry trees also spread their branches out to the sides when given enough room to grow; and cherries, too, are sometimes planted at crossroads.
At close range, cherries and hackberries can easily be told apart by their very different leaves. Even at medium range a cherry’s distinctive horizontally-striped bark will give it away. But I can distinguish these two trees at a great distance, with nothing more than a casual glance. One is clearly “hackberryish” and the other “cherryish.”
Unable to explain in words the meaning of “hackberryish” I was forced to take the people up to the tree and show them the tree’s characteristic leaves and berries. This little episode got me thinking about how we people actually learn to distinguish objects in the world around us. From my experience with trees, this learning process seems to occur in two major phases. The first of these is highly logical and deductive. It involves close observations of fine details, coupled with objective comparisons based on these observations.
The size and shape of a leaf, the pattern of leaf venation, the number and sharpness of the teeth along the leaf edge, the color and structure of the flowers, the form and color of the fruits, the thickness of the bark: these are all minute characteristics that vary from species to species, and provide a wealth of reliable details for objective observation and comparison of trees.
In this first phase, the objective observations and comparisons are repeated over and over. As readers of this column know very well, over the years I have found that sketching is a great aid in identifying and remembering the fine details. As this process continues, however, slowly but surely there evolves in my mind a more subjective image of what a particular tree should look like.
Of what is this subjective image composed? At one level of thinking, it can only be the sum of all the individual details. But then again there seems to be something else involved. A friend of mine, a lady very well versed in mystic art and philosophy, tells me that by constantly touching the different trees I have over the years learned to distinguish them by their aura!
I can’t say much either way about auras. If pressed, I would probably say that a subjective image like “hackberryish” is composed of various elements that register directly on the subconscious: such as overall shape of the crown; size, density and orientation of branches; and size, density, color and texture of leaves. Some leaves, for example, have hard, shiny surfaces that reflect light, while others have soft, velvety surfaces that absorb light.
The way a tree reacts to the wind may also help form a subjective image. Some wave their branches wildly, while others bend solemnly from the trunk. Still others flick their leaves over and up again. John Muir, the great 19th-century American naturalist and founder of the Sierra Club environmental organization, is said to have been able to distinguish different species of trees simply from the sound the wind made blowing through the branches.
Whatever a subjective image may be composed of, I do know that in my case at least it takes some time to form one. Most of the trees which I can identify at a distance are common local species. Whenever I travel to another region and encounter new species, I immediately revert back to the first phase, making my detailed sketches and observations and comparisons.
Some species of tree can be easily identified subjectively down to the level of genus, but not all the way to individual species. A good example of these are the hornbeams (shide, in Japanese, or Genus Carpinus). These Birch Family (Betulaceae or kabanoki-ka) trees grow to medium size, and will spread out if given enough room. They have thin bark that forms in distinct wavy vertical patterns of light and dark gray. Their crowns are dense, and the leaves small and light. In early spring the male catkins hang down in droves, and in autumn the branches are full of their distinctive clusters of seeds and bracts.
The hornbeam seeds are hard and round. By themselves they would simply fall down under the branches of the parent tree, where there would be no room to sprout. Each seed, however, stays attached to a small leaflike structure called a bract. The bract acts like a sail, catching the wind and dispersing the seeds all over the countryside.
There are about two dozen species of hornbeam worldwide, and five here in Japan. Three of the five are regulars in lowland and hillside woodlands. From a distance they all look alike, but close-up they can be readily distinguished by the shape of their leaves and bracts.
From a distance, I can usually tell that a tree is a hornbeam, but never which one. Maybe if I stand under them long enough, doing my yoga poses, I will, as my friend insists, eventually learn to distinguish them by their unique auras!
Short is a naturalist and cultural anthropology professor at Tokyo University of Information Sciences.