Scientific Name
Ulmus thomasii
Trade Name
Rock elm
Family Name
Common Names
Canadian cork elm, Canadian rock elm, Cork elm, Elm, Hickory elm, Rock elm
Regions of Distribution
North America
Countries of Distribution [VIEW MAP]
Canada, United States
Common Uses
Baskets, Boxes and crates, Building materials, Casks, Cooperages, Decorative plywood, Decorative veneer, Farm vehicles, Figured veneer, Food containers, Interior construction, Interior trim, Machinery parts, Millwork, Moldings, Packing cases, Pallets, Plywood, Skids, Trimming, Vehicle parts, Veneer, Wainscotting, Wheels
Environmental Profile
| Status has not been officially assessed |
Distribution Overview
This North American species occurs from southern Ontario, extreme southern Quebec and western New England southward to Tennessee, west to the far northeastern Kansas, and north to Minnesota. It grows in hardwood forests, and prefers moist to dry upland soils, especially rocky ridges and limestone bluffs. It is also reported to grow on flatlands.
Heartwood Color
| Brown | ||||||||||||
| Red | ||||||||||||
| Yellow | ||||||||||||
| Purple | ||||||||||||
| Orange | ||||||||||||
| Light brown |
Sapwood Color
| Red | ||||||||||||
| Brown | ||||||||||||
| Yellow | ||||||||||||
| Color not distinct from heartwood |
Grain
| Even | ||||||||||||
| Interlocked | ||||||||||||
| Straight |
| Straight | ||||||||||||
| Occasionally interlocked, but not always |
Texture
| Fine | ||||||||||||
| Moderately fine |
Luster
| Low | ||||||||||||
| Brownish | ||||||||||||
| Greyish |
Natural Durability
| Durable | ||||||||||||
| Moderately durable | ||||||||||||
| Non-resistant to powder post beetles | ||||||||||||
| Susceptible to insect attack | ||||||||||||
| Resistant to decay | ||||||||||||
| No natural resistance |
Odor
| No specific smell or taste |
Resin Content
| Heartwood has very low resistance to decay |
Used for dockwork, wharf construction and ship’s fenders because of its outstanding resistance to wear and tear
Kiln Schedules
| T6-B3(4/4) | ||||||||||||
| T3-B2 (8/4)US |
Drying Defects
| Checking | ||||||||||||
| Warping can be expected | ||||||||||||
| Checking |
Ease of Drying
| Slowly | ||||||||||||
| Dries well under good controlled conditions |
Liable to degrade excessively and shrink considerably
Kiln Drying Rate
| Naturally dries slowly |
Tree Size
| Bole length is 10-20 m | ||||||||||||
| Bole length is 20-30 m | ||||||||||||
| Sapwood width is 0-5 cm | ||||||||||||
| Sapwood width is 10-15 cm | ||||||||||||
| Sapwood width is 5-10 cm | ||||||||||||
| Tree height is 20-30 m | ||||||||||||
| Tree height is 30-40 m |
Blunting Effect
| High to severe | ||||||||||||
| Moderate effect |
Boring
| Fairly easy to very easy |
Cutting Resistance
| Fairly Difficult to Very Difficult to saw | ||||||||||||
| Difficult to saw | ||||||||||||
| Difficult to saw |
High density
Gluing
| Glues well |
Movement in Service
| Moderate dimensional stability after seasoning | ||||||||||||
| Medium |
Nailing
| Holds satisfactorily | ||||||||||||
| Growth rings fairly distinct |
Planing
| Fair to Good Results | ||||||||||||
| Fairly Difficult to Very Difficult | ||||||||||||
| Fairly Easy to Very Easy | ||||||||||||
| Very Good to Excellent Results | ||||||||||||
| Yields a clean surface | ||||||||||||
| Planes to a smooth surface | ||||||||||||
| Difficult to plane |
Resistance to Impregnation
| Heartwood is resistant |
Response to Hand Tools
| Easy to Work | ||||||||||||
| Fairly Difficult to Difficult to Work | ||||||||||||
| Difficult to machine |
Screwing
| Satisfactory characteristics |
Steam Bending
| Very good |
Polishing
| Fair to Good Results | ||||||||||||
| Cut surfaces are usually smooth and glossy |
Staining
| Stains well |
Varnishing
| Satisfactory |
Strength Properties
| Heavy |
Described as hard. High strength and shcok resistance
Numerical Data
| Item | Green | Dry | English |
| Bending Strength | 9163 | 15239 | psi |
| Crushing Strength | 652 | 1250 | psi |
| Hardness | 1294 | lbs | |
| Impact Strength | 59 | 69 | inches |
| Maximum Crushing Strength | 3822 | 6997 | psi |
| Shearing Strength | 1882 | psi | |
| Static Bending | 4508 | 7938 | psi |
| Stiffness | 1250 | 1710 | 1000 psi |
| Work to Maximum Load | 19 | 23 | inch-lbs/in3 |
| Specific Gravity | 0.57 | 0.63 | |
| Weight | 55 | 50 | lbs/ft3 |
| Radial Shrinkage | 5 | % | |
| Tangential Shrinkage | 8 | % | |
| Volumetric Shrinkage | 14 | % | |
| Item | Green | Dry | Metric |
| Bending Strength | 644 | 1071 | kg/cm2 |
| Crushing Strength | 45 | 87 | kg/cm2 |
| Hardness | 586 | kg | |
| Impact Strength | 149 | 175 | cm |
| Maximum Crushing Strength | 268 | 491 | kg/cm2 |
| Shearing Strength | 132 | kg/cm2 | |
| Static Bending | 316 | 558 | kg/cm2 |
| Stiffness | 87 | 120 | 1000 kg/cm2 |
| Work to Maximum Load | 1.33 | 1.61 | cm-kg/cm3 |
| Specific Gravity | 0.57 | 0.63 | |
| Weight | 881 | 801 | kg/m3 |
| Radial Shrinkage | 5 | % | |
| Tangential Shrinkage | 8 | % |
References
Boone, R.S., C.J. Kozlik, P.J. Bois and E.M. Wengert. 1988. Dry Kiln Schedules for Commercial Woods: Temperate and Tropical. United States Department of Agriculture, Forest Service, Forest Products Laboratory, General Technical Report FPL-GTR-57, Madison, Wisconsin.
Canadian Forestry Service. 1981. Canadian Woods – Their Properties and Uses. Third Edition. E.J. Mullins and T.S. McKnight, Editors. Published by University of Toronto Press, Toronto, Canada.
Little, E.L. 1980. The Audubon Society Field Guide to North American Trees – Eastern Region. Published by Arthur A. Knopf, New York.
Panshin, A.J. and C. deZeeuw. 1980. Textbook of Wood Technology, 4th Edition. McGraw-Hill Series in Forest Resources. McGraw-Hill Book Company, New York.
Rendle, B.J. Editor. 1969. World Timbers, Volume Two – North & South America (Including Central America and the West Indies). Published by Ernest Benn Limited, Bouverie House, Fleet Street, London.
USDA. 1987. Wood Handbook – Wood as an Engineering Material, Forest Service, Agriculture Handbook No. 72, Forest Products Laboratory, Madison, Wisconsin.
USDA. 1988. Dry Kiln Operators Manual, Preliminary Copy. Forest Service, Forest Products Laboratory, Madison, Wisconsin.