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SPECIAL INTRODUCTORY NOTE
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The European species, previously common, were some twenty years ago virtually wiped out by a fungal attack known as Dutch Elm disease. European grown timber is now no longer available to any significant extent though parcels of old veneer including burr-wood veneer can be found. The American and Canadian species have not been affected by the disease and nowadays are the only practical source for Elm timber.
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NAME/S
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European Species - principally English Elm (Ulmus procera), Dutch Elm(Ulmus Hollandica), Wych Elm (Ulmus glabra)
American/Canadian species - principally White Elm (Ulmus americana),Slippery Elm (Ulmus fulva), Rock Elm (Ulmus thomasi).
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SUB NAMES/S
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English and Dutch Elm is referred to as Red Elm and Nave Elm. Wych Elm is sometimes called Mountain Elm and Scotch Elm, White Elm is also known as Soft Elm and Orhamwood. Slippery Elm is sometimes called Red or Grey Elm, Rock Elm is also called Cork Elm.
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TRADE NAME/S
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Terms such as figured may be applied to describe unusual appearance characteristics. The name Burr Elm or Elm Burl is applied to wood that has a very convoluted grain structure which in the cut wood shows as whorls, curls, twists and birds eye features. Elm Burr-wood most often comes from growths that can develop around the base of the tree.
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APPEARANCE
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The appearance of White Elm and Slippery Elm is very similar to the European species. The sapwood is wide and pale brown while the heartwood is darker and is sometimes slightly red. The growth rings are distinct and create a pleasing figure, which is enhanced by some cross grain. Grain can be straight but is often Interlocked. This combination of features results in dissimilarity of grain appearance from log to log.In Rock Elm there is less distinction between sapwood and heartwood and the growth rings are less striking. The colour is pale brown, grain is generally straight and texture is finer than other Elm timber.
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ORIGIN
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European species occur predominantly in England, Wales and the near continent though Wych Elm is found in Northern Europe and Scotland. White Elm occurs over a wide area of eastern Canada and the USA, south as far as Texas.Rock Elm grows in the southeast of Canada and in the USA south from the lake states to Missouri and west to Nebraska.
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MECHANICAL PROPERTIES
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White Elm is fairly light in weight with a density of 560kg/m3 . It is tougher and stronger than European Elm.Rock Elm is heavier with density up to 750kg/m3 and is extremely tough. Neither is regarded as durable. The girth of White Elm can reach over 1m. Rock Elm is smaller with girth up to 600mm.
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AVAILABILITY
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White Elm and Slippery Elm are sold together as one variety. The American species are available as square-edged boards 25-100mm thick, up to 300mm wide and 3m. in length but may have to be specially ordered. Veneer is available usually crown cut. Burr-wood veneer is available from specialist suppliers.
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USE AS TIMBER CUTS FEATURES
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American White Elm and Rock Elm is durable in interior conditions and selected timber is suitable for interior joinery. Elm is prone to interlocking grain that can be troublesome during machining operations.Elm in the solid generally matches well in colour to the veneer form though it should be understood that veneers are taken from logs selected for absence of contentious features. It may not be commercially practicable to avoid such features in the solid material. Many features and marks are not exposed prior to the moulding operation and cannot be selected out. The wood is regarded as stable once properly dried.
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USE AS VENEER CUTS APPEARANCES
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Elm veneer is produced from selected logs in which unwanted characteristics are limited or not present. The logs are most often sliced to produce crown veneer. White Elm veneer (and the European) is of striking appearance, usually with a strong figure and some quartered grain at the edge of the sheet. When laid up the overall appearance is usually stripy. Rock Elm displays a much milder and more finely grained appearance.As each log has individual character, it is well to view the range of material needed in order to plan any requirement for matching. The best Burr Elm veneer displays tight and continuous burrs and is particularly effective when quarter matched as a feature panel with an inlaid surround. Supply of well-matched material needs to be planned for.
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RELATIVE COST/of 10
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Crown veneer 3. Burr-wood veneer 10
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PROPERTIES-MACHINING, FINISHING,JOINTING
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The solid material machines well though care is required in view of the probability that some interlocked grain structure will be encountered. The wood is somewhat coarse (less so in Rock Elm) but a good finish can be produced.Both solid wood and veneer take stain and polishes.
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SEASONING
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White Elm is said to season more easily and with less distortion than Rock Elm or the European species.
