520 A HANDBOOK OF CONIFER^E 



Var. recur vata, Hort. 

 Branches much twisted. 



Var, semperaurescens, Hort. 

 Young shoots and leaves with a golden tinge. 



Var. zebrina, Hort. 

 Foliage variegated with bands of green and gold. 



T. plicata differs from the other N. American species, T. 

 occidentalis, in its larger leaves, fewer resin glands on the foUage, 

 and by the silvery marks on the leaves on the underside of the 

 shoots. The cones have usually six fertile scales. 



It is widely distributed in W.N. America from sea-level to an 

 altitude of 6,000 ft., from Alaska, through British Columbia, W. 

 Oregon and Washington, to Mendocino County, California, in the 

 west, and eastwards to N. Montana and Idaho, occurring singly or 

 in groves amongst Douglas fir and other trees on moist lands or 

 near the banks of streams. 



Wood light, soft, brittle, fragrant, durable, easily worked, 

 heartwood light brown or reddish brown, sapwood paler. Used 

 very extensively for shingles, telegraph and telephone poles, 

 railway sleepers, building purposes and cooperage. The Indians 

 use the split trunks for the totem poles of their villages, of which 

 one is to be seen in Museum No. iii, at Kew. In British Columbia, 

 Washington, and Oregon immense quantities of wood are cut each 

 year, the tree being only second to Douglas fir in importance. 

 The wood is very durable and seedlings have been known to 

 spring up on fallen trunks, come to maturity and after being cut 

 down it has been found possible to utilize the wood of the original 

 fallen tree for shingles and other purposes. 



The following tests on green material were made by the U.S. 

 Department of Agriculture ^ : — 



Weight green (moisture 25 per cent., wood 75 per cent., 26 lb. 

 per cubic ft. 



Tension, strength across the grain, 210 lb. per square in. 



Compression, strength across grain at elastic limit, 310 lb. 

 per square in. 



Compression, crushing strength with the grain, 2,840 lb. per 

 square in. 



Shearing, strength with the grain, 720 lb. per square in. 



Bending, modulus of rupture (breaking strength), 5,200 lb. 

 per square in. 



Bending, modulus of elasticity (stiffness), 950,000 lb. per 

 square in. 



Hardness, weight required to haH-imbed a 0-444 in. steel ball, 

 345 lb. 



^ Catalogue of the Empire Timber Exhibition (1920). 



