154 TIMBER AND TIMBER TREES. [CHAP. 



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 faulty, 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 neverthe- 

 less 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 

 it occasionally happens in working this wood that 

 perfect nests, with fresh-looking eggs, are found deeply 

 buried in the log.* 



The sap-wood of Elm timber is generally from 1% 

 to 3 inches thick, but it forms an exception to the rule 

 which forbids the employment of sap-wood in architec- 

 ture, 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. 



* Acorns have been found in such positions, the stores of a squirrel having 

 been buried in a mass of the invading mycelium of a tree-destroying fungus. 

 (See "Timber and some of its Diseases," by Marshall Ward, p. 169.) 



