178 



TIMBER RESOURCES FOR AMERICA'S FUTURE 



species that, because of irregular grain, splits, 

 stresses, and brash centers, cannot be handled 

 well on the lathe. 



Utilization of Plant Residues 



Improvement in handling and processing equip- 

 ment, increasing demands for pulp and other 

 products, the creation of new markets and uses 

 for wood, have tended to, increase the utilization 

 of plant residues. 



During the past few years, pulp mills have made 

 increasing use of the slabs, edgings, and trim dis- 

 carded at sawmills; and the hardboard industry, 

 particularly in the West, has based its expansion 

 almost entirely on this kind of material. As only 

 limited amounts of bark can be tolerated, there 

 has been increasing use of mechanical and hy- 

 draulic barkers to remove the bark from logs as 

 they enter the mills or for later barking of the slabs 

 themselves. While most of the residues used for 

 pulp and hardboard come from the larger mills, 

 some progress is being made in the utilization of 

 slabs and other coarse residues at small center's of 

 concentration through the development of portable 

 chippers and improved equipment for faster and 

 easier handling. 



Veneer cores, already bark free, have become 

 especially attractive for pulp, and their use for 

 this purpose has grown steadily. A similar use 

 has developed for veneer clippings, particularly 

 on the West Coast, where supplies are plentiful 

 and cheap. 



While the growing use of residues for pulp is 

 perhaps the most spectacular, other uses for plant 

 residues have likewise expanded considerably 

 in recent years because of growing markets and 

 scarce timber supplies. Greater quantities of 

 sawmill and other coarse plant residues, for ex- 

 ample, are being diverted for remanufacture. 

 The development of processes and markets for 

 fine residues like sawdust and shavings has opened 

 up opportunities for better and more complete 

 utilization of these residues. 



Not to be overlooked is the progress made in 

 the use of both coarse and fine residues for char- 

 coal and a wide assortment of other derivatives 

 developed in carbonization, extraction, hydrolj^sis, 

 or other chemical utilization processes. There has 

 also been a definite trend towards integration of 

 industries where the residues of one become the 

 raw material for another. Thus through reduced 

 raw-material costs, utilization of residues has 

 become a more profitable undertaking. 



The Utilization Outlook 



Full economic use of the entire volume of woods 

 and plant residues may never be possible. Yet in 

 building up the Nation's timber supply to meet 



the ever-increasing demands of the future, advan- 

 tage must be taken of every possible opportunity to 

 make the timber we have go further. Recent 

 progress is evidence that many of the problems of 

 finding profitable ways of doing this are being 

 overcome. The outlook is for continued improve- 

 ment. 



Some of the improvement is expected to result 

 from closer utilization of growing stock in the 

 woods with a consequent reduction of logging 

 residues, some through reduction in amount of 

 plant residues due to better sawing and other 

 manufacturing practices and more complete utili- 

 zation of plant residues, and some through greater 

 use of dead and cull trees. Greater integration 

 of the timber products industries, both in the 

 woods and mill, is likewise expected to accomplish 

 more complete and advantageous utilization of 

 the timber that is cut or should be cut. And the 

 practice of relogging cutover areas should gain 

 momentum as better and more suitable equipment 

 for handling and transporting the material eco- 

 nomicall}' is developed, and as small portable saw- 

 mills are employed to a greater extent to process 

 the leftovers on previously logged areas in the 

 West. 



Present trends and anticipated progress in 

 utilization indicate an overall reduction of about 

 4 percent by 1975 in growing stock needed for a 

 given level of output of all products combined. 

 In other words, the total output which required 

 the cutting of 100 cubic feet of growing stock in 

 1952 will require cutting only 96 cubic feet in 

 1975. Whereas only an improvement of 2 per- 

 cent seems to be a reasonable expectation for 

 lumber, about a 14-percent improvement appears 

 in the offing for pulp wood, since a correspondingly 

 large proporticn is certain to come from plant 

 residues, tops, and dead and cull trees. 



This trend in the use of plant residues for pulp 

 very probably denotes the largest gains in utili- 

 zation that can be foreseen. More practicable log 

 and slab barkers will undoubtedly be developed 

 which will greatly extend the market possibilities 

 for use of coarse sawmill residues for pulp and 

 various types of hardboard. And better and more 

 efficient equipment for handling residues and 

 portable chippers now in the development stage 

 may be expected to substantially increase the 

 market potentials for residues from t>mall and 

 widely scattered concentrations. 



In addition to pulp, the use of plant residues in 

 remanufacture, in agriculture, and in chemical 

 utilization may be expected to grow in response 

 to continuing market demands, and as competition 

 for the available timber becomes more acute. In 

 this connection it seems reasonable that, as 

 markets and prices improve, much of the residue 

 volume that is now used for fuel will be sought for 

 pulp or put to other more advantageous uses. 



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