Elm

[Marc St Louis]

Elm is extremely variable in its bending characteristics, so many variations that I don't think I could list them all.  Here is a list of some I have found, some bad, some good and some excellent and I am sure I haven't seen them all

Some trees will have high bend resistance yet will chrysal fairly easily, these usually have a fair bit of reddish brown heartwood and they mostly have thin rings.  This wood is only good for backing strips on a low stress design IMO, or firewood

Some trees will have low bend resistance, they're almost like a rubber band.  This wood doesn't chrysal easily but quite often they will take more set than I like even with a heavy heat-treating.  This wood has very thick rings and a lot of sapwood.  Sometimes though you can find one of these types that is excellent once heat-treated.  They maintain their profile almost all the way though tillering and lose very little even after shooting.  This one is excellent wood but not the best I have seen

Some trees have fairly high bend resistance and don't chrysal easily but they will take set even with a heavy heat-treating.  These usually have quite a bit of sapwood with uniform medium thick rings.  This is decent wood

Some tree will have good bend resistance, don't chrysal easily and maintain a lot of induced reflex from heat-treating even after shooting.  These have variable ring thickness, meaning the rings change in thickness along the length of the tree, and a fair bit of sapwood.  This is good wood.

Then we come to the A+ trees.  These will always have medium thick uniform rings with a lot of sapwood.  The sapwood can have a yellowish tint or be an off white colour.  This wood always has a high bend strength, does not chrysal easily and keeps much of any heat-treated reflex that is put in even after shooting.

Very rare but sometimes you get a tree that is actually a bit weak in tension, unusual for Elm.  I don't know much about these but they are generally thin ringed, could be that factor that makes them weak.

The differences in all of these is species related but not always.  The ones that chrysal easily always seem to be Red Elm but there again there are exceptions.  Some of these exceptions could be related to growing conditions, I don't know.  The trees with thick rings invariably fall into the White Elm category.  Then there's the others.  Essentially there are just too many variables.  The only way that I have been able to tell is to cut the tree and make a high stress design with the wood.  I do tend to avoid Red Elm.  The density of the wood does play a part in how good it is most of the time but not always.

[penderbender]

Very interesting read mark! Cheers- Brendan

[Onebowonder]

Mark - thanx for the benefit of your experience here.  As it happens, it is most timely for me!  I just had a farmer friend call me last night to offer me some Elm logs from trees he just took down.  He was not sure what type of elm the tree was.  We are in SW Missouri.  I'm looking for a reference for trying to ID the species.  Any advice of a good link for such data?  He has retained some of the leaves and obviously the bark for me to evaluate.

...also, I was inclined to store the wood round, paint the ends, spray it down with pesticide, and leave the bark on.  Is that the correct method for Elm in your experience?  I already know to anticipate it being a BOOGER to split.

OneBow

[JonW]

I have cut quite a bit of Elm over the years looking for bow wood. I have found some quite good and some only good for firewood. I also wish I had a better grasp of indentifying the different types. I find most of it in my area is the type with very small leaves and some reddish heartwood. It is superior wood sometimes but most of the time only marginal bow wood. It responds very well to heat treatment and keeps reflex well. I really like this wood. I wish I could determine what makes some really good and some leaving me wishing I hadn't wasted my time.

[E. Jensen]

I've had pretty good luck with siberian elm.  So far at least, maybe in a few weeks I'll come back here crying.  ELB design, ~68", ~60#, heat treated, staying true so far.  Medium-thin rings, yellowish sapwood, more heart than sap.

[PEARL DRUMS]

Damn, Marc. Why didn't you tell me this before?

Holding out on me......

[PatM]

Apart from Red Elm all of those types are almost surely just individual variations of American Elm.


  This following statement gives an idea of what makes the tree unique and a factor that may indicate another species or just individual variation within the species.  Perhaps the "smaller cells" explains some of the wood variation.

  "For over 80 years, U. americana has been identified as a tetraploid, i.e. having double the usual number of chromosomes, making it unique within the genus. However, a study published in 2011 by the Agricultural Research Service of the USDA revealed that about 20% of wild American elms are diploid, and may even constitute another species. Moreover, several triploid trees known only in cultivation, such as 'Jefferson', are possessed of a high degree of resistance to Dutch elm disease, suggesting the diploid parent trees, which have markedly smaller cells than the tetraploid, may too be highly resistant to the disease"

[Jim Davis]

These common names have regional variations. Never have even read of a "white elm."  The American Elm is nearly nonexistent, being the prime victim of Dutch elm disease in the last century.

onebowonder, your elm logs are probably what goes by "winged elm" or " witch elm." Makes good bows generally.

Other names other elms in the eastern U.S. include slippery elm, cork elm, and red elm.

[PatM]

Slippery and Red are the same tree. Cork Elm is Rock Elm where we are. I have to look for a long time before finding any Red Elm or Rock Elm around here but I have seen isolated pockets of them.

[Frodolf]

Just today I put some oil on an elm (ulmus glabra) ELB, 50#/28". It's probably the fastest selfbow I ever made. The stave was unusually lightweight, as if was holding a stave of willow or something. From the 2" of reflex, 1" remains after tillering and shooting, no heat treatment. The mass ended up half an ounce lighter than mass principle recommends.

Marc, thank you for sharing. It's so difficult to try and figure out what makes one tree better bow wood compared to another, no matter the species I think. I've cut junipers that grow in "ideal locations" that ended up fluffy lightweight with massive rings, for example. A couple of questions though: do you take note of growing conditions? – nutrients, water, wind, etc? Any thoughts there? And have you noticed any difference in mass/thickness in the various qualities of elm you list? I'm guessing that's what you refer to as "bend resistance" (more bend resistance makes a thinner/lighter-in-mass bow)?

[JonW]

These common names have regional variations. Never have even read of a "white elm."  The American Elm is nearly nonexistent, being the prime victim of Dutch elm disease in the last century.

onebowonder, your elm logs are probably what goes by "winged elm" or " witch elm." Makes good bows generally.

Other names other elms in the eastern U.S. include slippery elm, cork elm, and red elm.

Jim are you sure winged elm and witch elm are the same? I thought Wych elm was a european species.

[GB]

Thanks for this info, Marc.  I don't have access to elm staves, but I've tried to make hickory backed bows from red elm boards.  Two of them chrysalled and one took a lot of set and performed subpar.  I'm willing to put some of the blame on my tillering, but I've made good bows from hard maple, hickory, and ERC boards from the same lumberyard.  So, I've given up on red elm.  They do carry a few grey elm boards, whatever species that is, and I'm tempted to try it someday.  Anyone have any experience with this grey elm?

[PatM]

Grey elm is American Elm and even Red elm is called Grey Elm. Hope that makes it clear. 

[Marc St Louis]

Bacteria work on Elm quickly so leaving the log whole is not recommended especially if it is sealed. 

As I said, I have found that Elm with little sapwood and a lot of heartwood to not be worthwhile making a bow out of.  It's very rare to find one of those to be good wood.  Still if it's all you can get your hands on then by all means use it, just don't stress the wood too much.  This is the Red Elm species also called Slippery Elm.

It's hard to say if the different variations are all American Elm, also commonly called White Elm.  There might be some crossing over with the new species brought over from other countries.  I have read at some point that young trees are less likely to get Dutch Elm, why you see so many young tree and hardly any old trees. 

Winged Elm and Wych Elm are 2 different species, the first is NA and the second from Europe.  Winged Elm does not seem to grow North of the border here.

Cork Elm does seem to be a variation of the Red or Slippery Elm.  There are some papers that say it is a Hard Elm, I have seen some research that separates the many species into Hard and Soft Elm.

Growing conditions are another factor that are hard to figure in.  I have cut Elm growing in very rich soil with rings 3/8" or more.  The wood was good but not excellent.  The best I have come across was wood with uniform growth rings 1/8" to 3/16" thick.  Some trees have fairly low density yet have a high bend resistance.  These usually chrysal easily and you can literally feel them give way as you tiller them past their point of failure.

This site http://www.fpl.fs.fed.us/research/centers/woodanatomy/index.php probably has the most information on the net.  I bought a CD years ago called Woods of the World.  It is comprehensive with more information on different species world wide than any other source I have come across

[GB]

Thanks for clearing that up, Pat.  Someday, when I've steeled myself for another disappointment, I'll give that grey elm a try.