42 



BULLETIN 343, U. S. DEPARTMENT OF AGRICULTURE. 



THE PINES. 



Both the California and Montana lodgepole pine (Pinus mur- 

 rayana) yield pulp of very good quality. The wood can be ground 

 under ordinary conditions and does not require the consumption of 

 a large amount of power. Satisfactory results are obtained when 

 the wood is ground at high pressures and at high speed, provided 

 the stone is somewhat dull. The color of the pulp from both varie- 

 ties compares favorably with that of white spruce, though the 

 Montana wood is somewhat lighter than the California. The resin 

 did not prove objectionable. Montana lodgepole pine yielded 



Fig. 30. — Eastern hemlock ( Tsuga canadensis). 



approximately 2,140 pounds of pulp (bone dry) per hundred cubic 

 feet of rossed wood, while California trees yielded about 1,920 pounds. 

 The difference was due to the greater age, larger size, and lighter 

 weight of the California wood. 



Western yellow pine {Pinus ponderosa) can be ground under a 

 wide variety of conditions. The pulp has a fairly long, coarse fiber 

 and is invariably soft. In color it tends toward a creamy, resembling 

 to some extent that obtained from jack pine. While the wood used 

 in the test contained considerable pitch, this did not cause much 

 trouble either in the grinding process or in the operation of the wet 

 machine. The wood used was cut in October, and it is reasonable 

 to suppose that material cut after the sap had gone down would 



