164 FOREST UTILIZATION WOOD USES AND ECONOMICS 



heat, moisture, and oxygen are favorable. Whenever any or all of 

 these are absent, decay is not possible. Among the most durable 

 species are black locust, the cedars and cypress, redwood, and black 

 walnut. White oak, cherry, persimmon, longleaf pine, and western 

 larch are also very durable. Among the least durable species are 

 black gum, basswood, aspen, beech, willow, sycamore, and lodgepole 

 pine. Other species occupy intermediate positions. 



2. THE PRINCIPAL SOURCES OF WASTE IN THE FOREST AND AT 

 MANUFACTURING PLANTS 



Great wastage has necessarily attended the conversion of our trees 

 into usable forms. A large portion of the trees felled in the American 

 forests is still wasted owing to the unfavorable economic conditions 

 and failure to find a profitable outlet for waste materials. Probably 

 from 70 to 80% of our wastage has been unavoidable. Much improve- 

 ment has marked the development of both logging and manufacturing 

 processes within recent years, so that this enormous loss has been 

 partially eliminated. Even under ideal conditions, as in European 

 practice, only about 80 to 90% of the total volume of trees is utilized 

 except under extremely favorable conditions which exist in some por- 

 tions of western and central Europe. Hodgson has determined that 

 more than 6 millions of cords of softwood, or 42 cords per acre, are 

 yearly left unused in the woods on logging operations in the Douglas 

 fir region. The degree of utilization is directly related to market 

 prices. High prices mean more complete and efficient utilization. 



The chief sources of waste in the woods are the generally non- 

 marketable tops, limbs, and branches; the cutting of unnecessarily 

 high stumps; also breakage and shattering in felling and log making; 

 defective trunks; and improper measuring of log lengths (perhaps to 

 avoid crook, crotches, large knots, and other defects). Further waste 

 results from the customary practice on the part of the public in re- 

 quiring lumber to be cut in even lengths instead of odd and even 

 lengths, unnecessarily liberal allowances for trimming log lengths in 

 the woods, losses in transportation, chiefly in driving logs in streams, 

 and losses incident to insect and fungus damage when logs are left 

 for considerable lengths of time during the warm season. 



The principal losses in manufacturing are due to the large slabs cut 

 from the sides of the logs at the sawmills, wide kerf cut by circular 

 saws instead of band saws which are used in the larger and more 

 modernly equipped mills, loss in bark which is occasionally used for 

 fiber boards and for insulation purposes as in some redwood, losses due 



