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AMERICAN FORESTRY 



THE "KNEE BOLTER" DOING HIS WORK 



The man operating the shingle machine is called a "knee bolter." With 

 his knee he operates the carriage and rotates the block as it goes against 

 the saw which takes off all the bark and sap. The block is then ready 

 to be passed to the shingle saw. This mill is located at Clear Lake, 

 Washington, in a famous shingle district. 



been fully discussed and exploited, so far as it militates 

 against the wooden roof. 



The table which follows shows the number of shingles 

 made from the several woods listed. The figures are 

 for 1915: 



Wood Output 



Cedar 9,500,908,000 



Cypress 1,31 1,750,000 



Yellow pine '. 578,307,000 



Redwood 447,197,000 



White pine 



Chestnut 



Western pine... 



Hemlock 



Spruce 



All other woods 



68,806,000 

 45,084,000 

 30,308,000 

 24,140,000 

 8,003,000 

 23,182,000 



Total 12,037,908,000 



Precautions are necessary if such roofs are to be safe- 

 guarded against fire, because wood when dry, and par- 

 ticularly when old and weatherworn,' is easily ignited. 

 Yet it must be in actual contact with fire, or subject to 

 excessive heat, before it will kindle ; and in spite of many 

 dangers, houses with wooden roofs are not burned much 

 more frequently than are buildings which have other 

 kinds of roofs. The roof is not the only source of 

 danger from fire. 



Chemists and engineers have carried out many experi- 

 ments to find ways of rendering wood immune to fire 

 danger. In certain directions, encouraging success has 

 been attained, though no method of making a wooden 



roof absolutely unburnable has yet been discovered. 

 Shingles may be treated with chemicals in a way to 

 greatly lessen their inflammability, and that is now being 

 done on a scale which bids fair to become commercial. 

 The high cost of the treatment is the chief obstacle in 

 the way of larger use of such shingles, but that draw- 

 back may be overcome in time. 



The strength of wood and its light weight in propor- 

 tion to its strength serve to excellent advantage in the 

 frames which support roofs. When wood is subjected to 

 stresses of certain kinds, it shows as much strength as 

 iron, if compared on the basis of their respective weights. 



Most roofs consist of two parts. The covering of 

 shingles, tile or whatever it may consist of, sheds the 

 rain or snow, and keeps out the sun and wind ; but this 

 covering must have supports, and these are as important 

 as any other part of the roof. These supports constitute 

 the second part of the roof. In the simplest form of 

 primitive constructed shelters, the brush, bark, or boards 

 composing the covering were laid from wall to wall 

 without supports of other kinds ; but that form is not 

 in use on many buildings of the present day. 



Not infrequently the supports of the roof are more 

 expensive than the actual covering. That holds true 

 particularly of large buildings, but between the largest 

 and the smallest there are many styles, each calling for 

 supports of different kinds and sizes. 



The rafters, ridgepole, and sheathing are sufficient for 



PACKING THE RED CEDAR SHINGLES FOR SHIPMENT 



The shingles are packed in bunches, about four bunches to the thousand, 

 for convenience in handling and counting. An expert packer will put up 

 140 bunches in a day of ten hours, if his hand is true and his eye is 

 quick. Above the packer's head may be seen the sticks and the strap 

 irons for binding the bunches. 



