196 A NATIONAL PLAN FOB AMERICAN FORESTRY 



types of wood pulp. Considerable old paper also mingles with new 

 pulp in various papers, and pulp derived from nonwoody plants 

 mingles with wood pulp in fine papers. 



Newsprint, cheap magazine, cheap catalog, and similar papers, are 

 made mostly of mechanical pulp, that is of uncooked wood mechan- 

 ically ground into a pulp. Only the relatively soft, light colored, 

 nonresinous spruces, firs, and hemlocks are suitable for the manu- 

 facture of mechanical pulp or are used enough to be considered com- 

 mercial sources for this process. The mechanical process is the 

 cheapest of all, and the pulp yield is by far the greatest. The quality 

 of the pulp, however, is so low that in the manufacture of even cheap 

 papers considerable quantities of longer and stronger-fibered pulp 

 are added. Of our total wood-pulp production, mechanical pulp 

 comprises about a third. 



The stronger and better-grade papers are made of pulps manu- 

 factured by one of the three standard chemical processes sulphite, 

 sulphate, or soda. In each of these processes a large portion of the 

 wood is removed, leaving fibers consisting of almost pure cellulose. 

 This is accomplished by cooking chips of the wood with a chemical 

 under steam pressure. 



Some classes of book, wrapping, bond, and tissue papers are made 

 largely from sulphite pulp, and considerable sulphite is used in 

 mechanical papers. The sulphite process is a little more expensive 

 than the other chemical processes, and the pulp yield is only about 

 half as large as in the mechanical process ; but the pulp is very strong 

 and can be readily bleached to a high degree of whiteness. The woods 

 used in the sulphite process are the same as in the mechanical process ; 

 the light colored, nonresinous softwoods, such as spruce, fir, and 

 hemlock. Sulphite pulp accounts for about a third of the wood pulp 

 produced in this country. 



Kraft or wrapping paper and high-test fiber board are made from 

 sulphate pulp. The standard sulphate process is a little less expensive 

 than the sulphite process; the yield of pulp is about the same. Any 

 long-fibered wood can be used for sulphate pulp, even one which 

 contain resins and other alkaline-soluble materials. Sulphate pulp 

 constitutes about a fifth of our total wood-pulp production. 



Book, lithograph, and envelope papers are very often made from 

 a mixture of sulphite pulp and pulp made by the soda process. This 

 mixture gives a sheet of paper which is highly esteemed by printers. 

 The soda process can be applied to softwoods without difficulty, but 

 it is used almost entirely for the reduction of such hardwoods as 

 aspen, cottonwood, beech, birch, and gum. Soda pulp is sometimes 

 used alone in the manufacture of some of the cheaper, bulkier book 

 papers which have very low strength requirements. Of our total 

 wood-pulp production, soda pulp constitutes only about a tenth. 



With the above facts as to pulping processes and to woods suited to 

 them as a background, the availability of present pulpwood supplies 

 may be discussed region by region. 



REGIONAL SUPPLIES 



New England, Middle Atlantic, and Lake regions. The spruce 

 forests in New England and New York met the combined require- 

 ments for both mechanical and sulphite pulps better than those of 

 any other section of the country, so that it has been here, and later in 



