Page:Timber and Timber Trees, Native and Foreign.djvu/245

XXVII.] The wood is somewhat darker in colour than the Wych, is tough, hard, and of the same porous and flexible character, but being more frequently subject to star-shake, it is considered to be an inferior variety, and is consequently less sought after. It is not generally so suitable for boat-board as the Wych Elm, but for any ordinary purpose it might be used as a substitute for either of the other kinds. In commerce it is known as the Dutch or Sand Elm.

The English Elm trees are remarkable as being among the first in leaf in the spring, and the latest in shedding them in the autumn.

THE CANADA ROCK ELM TREE (Ulmus Americana)

is found growing abundantly in the low woods of North America, from New England to the Carolinas. It attains moderate dimensions, with a clean straight stem, and few heavy branches, and yields timber for the market in logs of from 20 to 40 feet in length and from 11 to 16 inches square.

The wood is whitish-brown in colour, hard, tough, and flexible, with a fine, smooth, close, silky grain; and as it has only a small quantity of sap-wood it can be worked up closely and economically. It is necessary, however, to remove the sap in the conversion of the log, as, unlike that of the English Elm, it is of a perishable character.

Rock Elm is often substituted for the English common Elm for garboards and planking in ship-building, as it is very durable when employed under water; it is also used for ladder steps, gratings, &c., on account of its clean whitish appearance; and owing to its flexible character it is frequently used in boat-building. It cannot, however, be used with advantage in bulk, or