Since I was checking it out, I thought I would dig into an interest of mine. My favorite all-time tree is the mighty American Sycamore, Platanus occidentalis. For some reason, my nose is attuned to the smell of the sycamore, and I can smell one a quarter-mile away, even in a mixed forest. So, for obvious reasons, I've always felt the sycamores were calling out to me, and as my approach confirms their presence, I've always smiled as on the approach of an old friend. I've spent many an hour parked beneath the boughs of big, old sycamores.
But I faced an interesting challenge when I first moved to State College. There are several streets in the area of the university that are lined with sycamores, or so I thought...but I could smell them only weakly, if at all. Then one day, while pontificating over the meaning of life related to the temperature of beer with my friend, colleague, and urban tree scientist Bill Elmendorf, he revealed to me that most of the trees in question were London Plane Trees, Platanus x acerifolia. I was shocked, shocked, to discover that my intimate Platanus friendship had been compromised by these mixed-breed intruders and pretend sycamores.
|Under the Plane Tree. Frontispiece to A Tale of Two Cities. Image scan and text by Phillip V. Allingham on http://www.victorianweb.org/art/illustration/phiz/7d.html|
For me, the sycamore has that great smell, and the plane tree only does if you use your imagination.
So, I naturally wondered, how does their wood differ? I've never examined them side-by-side, so Inside Wood gives me that opportunity.
First, the American Sycamore, Platanus occidentalis. From Inside Wood I find it to have the following anatomical features...
|1||Growth ring boundaries distinct|
|13||Simple perforation plates|
|14||Scalariform perforation plates|
|15||Scalariform perforation plates with <= 10 bars|
|16v||Scalariform perforation plates with 10 - 20 bars|
|21||Intervessel pits opposite|
|25||Small - 4 - 7 µm|
|30||Vessel-ray pits with distinct borders; similar to intervessel pits in size and shape throughout the ray cell|
|41||50 - 100 µm|
|49||40 - 100 vessels per square millimetre|
|50||>= 100 vessels per square millimetre|
|53||350 - 800 µm|
|62||Fibres with distinctly bordered pits|
|66||Non-septate fibres present|
|69||Fibres thin- to thick-walled|
|77||Axial parenchyma diffuse-in-aggregates|
|86||Axial parenchyma in narrow bands or lines up to three cells wide|
|93||Eight (5-8) cells per parenchyma strand|
|98||Larger rays commonly 4 - to 10 seriate|
|99||Larger rays commonly > 10-seriate|
|102||Ray height > 1 mm|
|104||All ray cells procumbent|
|114||<= 4 / mm|
|136||Prismatic crystals present|
|138||Prismatic crystals in procumbent ray cells|
|139||Prismatic crystals in radial alignment in procumbent ray cells|
|154||More than one crystal of about the same size per cell or chamber|
|164||Europe and temperate Asia (Brazier and Franklin region 75)|
|165||Europe, excluding Mediterranean|
|166||Mediterranean including Northern Africa and Middle East|
|167||Temperate Asia (China), Japan, Russia|
|182||North America, north of Mexico (Brazier and Franklin region 80)|
|192||Wood of commercial importance|
|194||Basic specific gravity medium, 0.40-0.75|
|196v||Heartwood colour darker than sapwood colour|
|197||Heartwood basically brown or shades of brown|
|200||Heartwood basically white to grey|
But this is the same list of features for Platanus x acerifolia, and other related species, Plantanus racemosa, Platanus orientalis, Platanus wrightii, and Platanus mexicana. So, for distinguishing one from the other, I'll have to go to the photos provided.
First, I browsed the twenty-eight images for sycamore on the site. Unfortunately, there are only two images of plane-tree wood. So, I had to compare the two most comparable images of sycamores. Fortunately, the two images of plane tree were provided by a certain Hans Beeckman, and that same person also had taken two comparable images of sycamore. Let's compare.
First, let's take a look at the transverse images of each.
|Platanus occidentalis. |
Platanus x acerifolia.
From these two samples, we see an anatomical feature of the genus: large and fairly numerous rays, which are the vertical lines in the photographs. It seems to me that the plane-tree sample shows a more uniform width between and of the rays, but this might easily be a difference in the sample. However, it is interesting to note that in Dr. Hoadley's book, in the transverse photo of sycamore on page 118, the rays also seem to vary in size. Hmmm...now I'll have to get many samples of each and make my own study. For his part, Dr. Hoadley states that the woods are "very similar" and implies that they, like the American and European species of beech, are difficult to distinguish from each other.
Next, let's take a look at the tangential images provided. Occasionally, tangential images can provide clues even when transverse images are too similar to call. So, we'll see if that happens in this case.
Platanus x acerifolia.
Well, I've been staring at them for about ten minutes now, and I don't see any difference that seems to be real. (The plane-tree sample is stained a little darker and is a little better focused.) By the way, a tangential view of wood is essentially looking at each ring of tree growth from the side...imagine a log with bark peeled off, and looking at the inner surface, but flattened. That is a tangential view...a microscopic view of the surface of flat-sawn lumber.
So, I'll have to conclude that the wood of sycamore and plane-tree is the same anatomically, and leave it to experts like Drs. Wheeler and Hoadley to weigh in and tell us otherwise. Perhaps some of you Go Wood readers are experts in the area and can comment below.
I forgot to mention...Dr. Elmendorf also said that plane-trees are more greenish-gray, whereas sycamore is more whitish-gray. I always thought that green (not dry) sycamore wood was a little greenish. Wood color differences tend to dissipate in the kiln-drying process, so I would be interested if anyone out there knows if they retain that color difference in dried wood.
Well, that's a little exercise in using the Inside Wood database to investigate something I've been wondering about. My conclusion: from a wood standpoint, they are the same tree.
But my nose knows better.