Page:Timber and Timber Trees, Native and Foreign.djvu/239

XXVII.] rapidly; therefore, the surveyor, in selecting this wood, should, if he requires it for any purpose where durability is an object, decline to take any but fresh-cut logs, since, if they have been left for more than about ten to twelve months exposed to the weather, they will be liable to prove doated, and very possibly may have changed from the natural brown to a yellowish colour, which is a sure sign of a deterioration in the quality. The bark of Elm usually falls off in about ten to sixteen or eighteen months after the tree is cut down, the surface after this gets blanched by exposure, and there are few logs that have been felled so long that are quite free from incipient decay.

There is almost no heart, cup, or star-shake in the common English Elm, but the defects are often nevertheless of a very serious character, and are chiefly occasioned by the rough treatment it is subjected to in the way of pruning—the knots or root end of the branches being left exposed, decay and wet-rot frequently soon follow, then hollow places are formed in the centre, and the tree is ruined. Birds frequently build in these cavities, and on several occasions in the course of my experience in working this wood, perfect nests, with fresh-looking eggs, have been found deeply buried in the log.

The sap of Elm timber is generally from 1½ to 3 inches thick, but it forms an exception to the rule which forbids the employment of sap-wood in architecture, as all parts of it have been proved to be equally durable. The waste, therefore, to be incurred in the conversion of the log is very small, provided always that the planks and boards are only cut as they are required. This precaution is considered necessary, owing to the great liability of the planks to warp or twist, which would soon render them unfit for use.