Date: 2011-06-01
Gene Wengert, ewengert@wisc.edu
Bold looking, tough acting.
American elm features interlocked grain which makes for high shock resistance.
American elm (Ulmus americana) and slippery elm (U. rubra), two of six species of elms that are found in the North America, are known together as soft elms. Rock, winged, cedar and September elm are known as hard elms. The hard elms are 25 percent heavier, and correspondingly stronger and stiffer, than the soft elms. American elm is certainly know for the wonderful shade trees of years past. It would not be unusual to have these trees rapidly grow to 100 feet tall and spread out to shade a 60 foot radius in the cities. I can remember elm streets that appeared like a dark tunnel when the elms on both sides of the street touched. In the spring, the little propeller-like seeds would spin down. I remember the neighborhood kids splitting the seed open lengthwise about ½ inch and then sticking the propeller on our noses so we had a nose longer than Pinnochio! I also remember parking under an elm tree and getting sappy drips all over the car. What a mess!
Then came the Dutch elm disease, actually a fungus, that essentially destroyed all these beautiful city elms, as well as the forested American elms as well. The good news is that some fungal resistant trees seem to be located and could be used for breeding. Time will tell.
To hockey fans, elm is their favorite wood, as most hockey sticks are made of elm. Why use elm for these sticks? The wood is very tough and has extensive interlocked grain. Interlocked grain means that the lengthwise grain from year to year goes different directions instead of being perfectly vertical in the tree, basically intertwining. As a result it is very difficult to split the wood; a characteristic obviously desired for hockey sticks -- the wood has high shock resistance. Likewise, interlocked grain means splitting elm for firewood can be nearly impossible.
When used above ground, the wood is resistant to decay even when permanently wet. In fact, hollowed trunks were widely used as water pipes during the medieval period in Europe.
The heavy ring pattern (ring porous grain like oak) combined with interlocked grain results in a very bold appearance or character to the wood, which is why it finds widespread use in paneling. I am surprised that more furniture and cabinetry don’t use elm; it certainly has a nice appearance. The elms are also excellent bending species as they are quite easy to bend, due to the interlocked grain, without breaking or cracking. However, this interlocked grain also means that warp is likely when drying if drying isn’t perfect and that machining requires special care.
Updated: Jun 02, 2011
This article appeared in CabinetMakerFDM, July 2011. ©Copyright 2012, All Rights Reserved.