No less than five varieties of this tree are found in Great Britain, besides which it flourishes in many parts of Europe and in America.
The principal varieties of this timber are as follows: -
The Common English or Rough-leaved Elm (Ulmus cam-pestris), found in England, France, and Spain.
The colour of the heartwood is a reddish brown. The sapwood is of a yellowish or brownish white, with pores inclined to red. The medullary rays are not visible. The wood is porous and very twisted in grain.
The wood is very strong across the grain; bears driving nails very well; is very fibrous, dense, and tough, and offers a great resistance to crushing. It has a peculiar odour, and is very durable if kept constantly under water or constantly dry, but will not bear alternations of wet and dry. Is subject to attacks of worms. None but fresh-cut logs should be used, for after exposure, they become covered with yellow doaty spots, and decay will be found to have set in. The wood warps very much on account of the irregularity of its fibre. For this reason it should be used in large scantling, or smaller pieces should be cut just before they are required; and for the same reason it is difficult to work. One peculiar characteristic of elm is that the sapwood withstands decay as well as the heart.
If elm timber is stored it should be kept under water to prevent decay.
The timber is very free from shakes, but frequently contains large hollow places caused by rough pruning and subsequent decay.
Elm is used in many situations where it is subjected to continual wet - namely, for piles, parts of pumps, pulley blocks, keels and planks under water in ships, heavy naval gun carriages, coffins, naves and felloes of wheels, stable fittings, etc.; also for various purposes by carpenters, turners, and cabinetmakers.
The wood is of a somewhat lighter colour than the common elm. It is clean and straight in grain, tough and flexible, and used for the naves of wheels and for boatbuilding.
The Dutch Elm (Ulmus major) and the Corkbarked Elm (Ulmus suberosa) both furnish inferior timber.