Orme

Overview and range in Europe

Three native elms supply European elm timber: field elm (Ulmus minor), wych elm (Ulmus glabra) and European white elm (Ulmus laevis, also called fluttering elm). The European Atlas of Forest Tree Species gives their ranges as follows. Wych elm is the most northerly, reaching Norway up to the Arctic Circle and eastward to the Urals; in the south it is found only in the mountains. Field elm does best in southern Europe, reaching the Baltic Sea at its northern limit and extending south to Algeria, Israel and north-east Iran. European white elm ranges from central France to the Urals, from southern Finland to Bulgaria and Crimea. EUFORGEN puts the wych elm northern limit in southern Finland, which differs from the Atlas; I report both.

Habitats differ, which affects log supply. According to the Atlas, wych elm prefers moist, rich soils in cool-summer forests; European white elm occurs in riparian forests along large rivers such as the Rhine, Elbe and Danube, below 300 m, on periodically flooded soils; field elm is a light-demanding, fast-growing riparian pioneer that spreads by root suckers. EUFORGEN adds that wych elm hybridises readily with field elm, and hybrids such as Ulmus hollandica occur in Flanders.

Dutch elm disease (DED) dominates the supply picture. Forest Research (UK) describes two outbreaks: a first epidemic around 1910 in north-west Europe, caused by Ophiostoma ulmi, which subsided by the 1940s after European losses of 10-40% of elms in several countries; and a far more destructive second outbreak from the 1960s, caused by the more aggressive O. novo-ulmi, reportedly brought to the UK on imported infected elm logs from North America. In Britain about 20 million mature elms died within a decade out of an estimated more than 30 million. The Atlas dates the two epidemics to the 1920s and 1970s, a discrepancy between sources that I leave unresolved. EUFORGEN reports that surviving wych elm populations are now often young or sprout-derived, with low regeneration.

Appearance and identification

Elm is a ring-porous hardwood with obligatory heartwood. The LWF leaflet on European white elm (Bavarian forest institute, Risse and Richter) describes 1-3 rows of large earlywood pores, often tylosed, and latewood pores in wavy tangential bands. The Wood Database describes wych elm as having light to medium reddish-brown heartwood with usually well-defined paler sapwood, interlocked grain and a somewhat coarse, uneven texture.

LWF gives the species differences. Field elm: sapwood about one third of stem diameter, yellowish-white to grey; heartwood grey to red-brown, sometimes dark red to chocolate brown. Wych elm: sapwood slightly over one third, heartwood similar but light brown. European white elm: milder pale grey to yellow-brown heartwood, often barely distinct from sapwood when dry, and the widest sapwood of the three, up to two thirds of the diameter. On tangential faces elm shows a fine jagged double figure between prominent earlywood bands, which LWF calls the key identifier. The wood darkens in light. LWF says species cannot normally be identified from anatomy alone, because ring width strongly affects structure, and the trade does not separate them: all native elms are sold together as "Rüster" in German-speaking markets. Freshly worked wood smells unpleasant (LWF); the Wood Database says wych elm has little odour once dry.

Properties that matter

Elm is a medium-density hardwood with good elasticity but only moderate bending strength. The table keeps European data and North American data apart: American elm (Ulmus americana) and other American species are different species and their figures should not be applied to European timber.

Property	Value	Source	Region / note
Density, wych elm	605 kg/m3 at 12% MC; SG 0.49 basic, 0.61 at 12%	Wood Database	Europe (species); specimen origin not stated
Density, elm in general	0.65 g/cm3 mean air-dry (range 0.48-0.86)	LWF Wissen 83	Germany; general elm values, species mix not stated
Janka hardness, wych elm	4,400 N (990 lbf) at 12% MC	Wood Database	Europe (species)
Bending strength	98.2 MPa (wych elm; MC not stated); 81 N/mm2 (elm general)	Wood Database; LWF	Europe; different sources
Modulus of elasticity	11.14 GPa (wych elm); 11,000 N/mm2 (elm general)	Wood Database; LWF	Europe
Compression parallel	46.3 MPa (wych elm); 51 N/mm2 (elm general)	Wood Database; LWF	Europe
Tensile parallel / impact work	80 N/mm2 / 60 kJ/m2	LWF	Germany, elm general
Brinell hardness	58-63 N/mm2 parallel; 27-37 perpendicular	LWF	Germany, elm general
Shrinkage (LWF)	L 0.3%; R 4.6-4.8%; T 6.9-8.3%; vol. 11.8-13.8%; T/R about 1.9	LWF Wissen 83	Germany, green to oven-dry
Shrinkage (Wood Database)	T 12.4% (green to oven-dry)	Wood Database	Wych elm; other directions not given
Durability class	4 (heartwood, EN 350-2)	LWF Wissen 83	Stated for European white elm
American elm density	560 kg/m3 at 12% MC; 530 kg/m3 (importer)	Wood Database; Gabarro	North America
American elm strength	Janka 3,690 N; MOR 81.4 MPa; MOE 9.24 GPa; crushing 38.1 MPa	Wood Database	North America; Janka at 12% MC, others not stated
American elm shrinkage	R 4.2%, T 9.5%, vol. 14.6%, T/R 2.3	Wood Database	North America

LWF compares elm with oak (0.71 g/cm3), ash (0.70) and maple (0.63): similar density, lower tensile and bending strength than oak and ash, similar compressive strength and impact work, and a lower tangential shrinkage than oak. LWF says strength improves with wider rings and that European white elm is generally slightly lower than the other elms.

There is a notable discrepancy: the Wood Database gives wych elm tangential shrinkage of 12.4%, while LWF gives 6.9-8.3% for elm. I cannot reconcile these from the pages; they may reflect different species, specimens or methods, and the Wood Database does not state the origin of its samples. The Wood Database also calls wych elm's dimensional stability poor, whereas LWF calls elm's shrinkage more favourable than most compared species; treat stability as uncertain.

Sawing and log handling

LWF recommends quick processing and sawing after felling to prevent greenish, oxidative discolouration. Contact with iron when wet can cause grey iron-tannin staining, weaker than in oak or larch (LWF), so steel stickers and wet-board contact are still best avoided.

The Atlas says European white elm has lower density and is cross-grained, which makes machine cutting difficult and causes defects. LWF finds hardness problems in sawing, planing and milling, particularly for wide-ring, denser wood. The Wood Database says interlocked grain makes wych elm challenging to work, especially on quarter-sawn surfaces, and that the same grain resists splitting. No open source gave blade, feed or yield figures.

Dutch elm disease affects supply rather than sawing practice. Forest Research says infected trees are usually destroyed, typically burned on site, and that authorities may exceptionally allow removal to another place for destruction. I did not find an open rule on whether logs from infected trees may be sawn and moved in each country, and I do not state one. The disease symptoms include a ring of dark brown staining in the outer wood (Forest Research); this is a diagnostic sign, and my inference is that logs from affected trees may carry stained outer rings. No source quantifies the effect on yield.

Drying

The sources I could open are thin on elm drying. LWF states that freshly felled elm has a high moisture content and needs controlled, gentle drying to prevent cracking and warping, and gives no schedule. The Wood Database has no drying section for wych elm or American elm; its poor-stability remark for both is the nearest guidance. Gabarro, an importer, says American elm is prone to "chafing" during drying without explaining the term, and I do not interpret it.

For North America, a Virginia Tech wood-technology page lists kiln schedule codes (examples that appear are T6-B3 and T3-A1) for American, rock, slippery, winged and cedar elm in thicknesses from 4/4 to 16/4, but the table was garbled and does not map codes to thicknesses. The US Forest Products Laboratory kiln schedule chapter (woodweb copy) lists American, slippery and rock elm in its general tables, but the extracted values were missing. I therefore cannot give any elm schedule, and I am not inventing one. A Chinese abstract on Asian elms links drying defects to high initial moisture and large dry shrinkage; I use it only as a general warning, not for European species.

Inference: interlocked grain and high initial moisture suggest a conservative schedule; verify any published elm schedule with sample charges.

Machining, gluing and finishing

LWF reports that finishing and coating pose no problems, attributed to low heartwood extractive content, and nails, screws and glued joints work without problems. Turning, knife work and steam bending are easy. Hardness makes planing and milling problematic, and sanding can roughen the surface. The Wood Database agrees that wych elm glues, stains and finishes well, bends well with steam and holds fasteners well, but warns of tear-out or fuzzy surfaces when planing interlocked grain.

For American elm, the Wood Database gives the same working notes, and Gabarro rates sawing easy, gluing very good, nailing and screwing good and finishing very good, and says the contraction coefficient is moderately "nervous" with a tendency to bend. Gabarro's rating is for American elm (eastern Canada and the US Midwest), so it is not applied to European elm here. The Wood Database reports elm as a sensitiser (eye and skin irritation).

Durability and treatment

Elm is not a durable timber in a standards sense. LWF assigns heartwood to class 4 under EN 350-2 (this statement is made for European white elm) and says it is unsuitable for outdoor exposure or damp rooms. The Wood Database rates wych elm non-durable and insect-susceptible. The Atlas, in contrast, says elms have exceptional resistance to water decay and cites underwater piles, shipbuilding and water pipes. One possible reading (inference) is that the Atlas refers to permanently submerged use and LWF to weathered or damp-air exposure; neither source tests this, so treat it as open.

On treatment, LWF reports sapwood as very well impregnable and heartwood as moderately to difficult because of partial tyloses; it also mentions laboratory-scale thermal-moisture modification studies for elm. For American species, Virginia Tech rates heartwood slightly or non-resistant to decay (North America).

Typical uses and market notes

LWF names interior fit-out in solid wood or veneer (wall and ceiling cladding, furniture, staircases, doors, parquet), decorative instruments, turnery, knife handles, cutting boards, gun stocks and toys. Wheelwrighting, mill wheels and boatbuilding are now marginal. Elm burr (Maser) is valued for veneer, marquetry, carving and pipe bowls, and LWF says European white elm forms burrs more often than other elms. The wood is not used for structural or load-bearing purposes. The Atlas lists furniture, flooring and firewood. The Wood Database adds boxes, baskets and hockey sticks.

On market, the Wood Database says wych elm is moderately priced in Europe and that availability from mature trees has greatly declined because of DED. LWF says availability is severely limited, so use is restricted to few applications and small volumes, and that round wood, sawn timber and knife veneer are supplied. LWF gives no prices and says burrs are expensive without figures. I have no verified prices.

What is uncertain or varies

• Species-specific figures are sparse. LWF's general "elm" values do not state the species mix, and the Wood Database figures are for wych elm only, with unknown origin.
• Shrinkage figures conflict between the Wood Database (tangential 12.4%) and LWF (6.9-8.3%).
• The EN 350-2 class 4 is stated for European white elm; I assumed no class for field or wych elm.
• No drying schedule could be read. American elm schedule codes were not decipherable.
• The Atlas and Forest Research date the two DED epidemics differently (1920s/1970s vs about 1910/1960s onward).
• No open source on handling or grade effects of DED-affected logs; no prices.
• English elm (Ulmus procera), the species hit hardest by DED in Britain, is not described in the wood-property sources I opened.

Key points

• Native elms are sold together as one product; species cannot be reliably separated in sawn wood.
• Density is moderate (605 kg/m3 for wych elm per the Wood Database; 0.65 g/cm3 for elm per LWF) with good elasticity but only moderate bending strength.
• Interlocked grain makes planing and milling difficult; finishing, gluing and steam bending work well.
• Saw quickly after felling to avoid discolouration, and dry gently; no verified schedule is given here.
• Heartwood is class 4 in the one EN 350-2 statement found (European white elm): interior use.
• Dutch elm disease has cut supply sharply; keep American elm data separate from European elm.