of the average saw-timber cut of all species in the 

 region for the period 1925-36, inclusive, and only 

 53 percent of the rate for the period 1937-39, 

 inclusive. Virtually all cutting has been in the 

 pine types. 



The allowable cut under sustained yield can be 

 materially increased by two means — first, by 

 changing cutting practice to a light selection sys- 

 tem; second, by cutting in the nonpine saw-timber 

 stands. By cutting on a maturity-selection basis, 

 removing in each cycle only 50 percent of total vol- 

 ume per acre, the allowable annual sustained-yield 

 cut for the pine types is increased 21 percent, total- 

 ing 1,126 million board feet. This increase is justi- 

 fied by the increased speed with which virgin forest 

 is converted to a condition of net growth under a 

 system of lighter volume removal per acre, and 

 the consequent saving in mortality. Within the 

 limits assumed for volume removal per acre, it 

 is obvious that the less volume removed from any 

 one acret he greater is the sustainable cut for the 

 entire area, provided that cut is confined to the 

 most mature and the least thrifty trees in the 

 stand. Assuming a volume per acre removal of 

 75 percent of the virgin stand on privately owned 

 pine lands and 50 percent on those in other 

 ownerships, the allowable cut from this type 

 group is 1,069 million board feet. 



The sustainable annual cut from the nonpine saw- 

 timber types is 387 million board feet, but until 

 there is greater assurance of their ultimate economic 

 availability and utilization, they can be given little 

 weight in balancing the timber budget. The pon- 

 derosa pine types contain 16 percent by volume of 

 so-called inferior species. An eventual increase in 

 the use of nonpine species is anticipated; in fact, 

 unless use of them is increased, the sustained-yield 

 capacity of the type group will be reduced. Only a 

 negligible amount of ponderosa pine occurs in the 

 nonpine types. 



Under reasonably intensive silvicultural practices 

 and protection from fire and insects, the region's 

 ponderosa pine types could in theory maintain an 

 ultimate annual production of 1,404 million board 

 feet; the nonpine types, 589 million. However, it is 

 doubtful if this level of productivity could be at- 

 tained in less than a century, even if the entire forest 

 area were put under sustained-yield management 

 immediately. 



The Situation Within the Units 



The advantages of sustained-yield management 

 are many but they may be generalized into two: 

 (1) Assurance of a continuous supply of forest prod- 

 ucts to the consuming public, and (2) assurance of 

 the permanence of the communities and economic 

 institutions that are built around and are dependent 

 upon the wood-using industries. Although an anal- 

 ysis on a regional basis is adequate from the stand- 

 point of the consuming public, it gives a grossly in- 

 adequate portrayal of the community problems. 

 For this purpose individual and coordinated case 

 studies by production units are indispensable. Such 

 studies are beyond the province of the present 

 report, but analysis of sustained-yield capacities by 

 forest-survey units materially localizes the problems 

 involved and adds to the practical usefulness of the 

 calculations. 



From table 30, comparing allowable cut by three 

 classes of cutting practice and by type group with 

 recent rates of saw-timber cut and ultimate sus- 

 tained-yield capacity, it is apparent that in no unit 

 can the 1937-39 rate of saw-timber production be 

 maintained in the ponderosa pine types, regardless 

 of the intensiveness of forestry that is practiced. 



Although future curtailment can be materially 

 reduced by adopting improved cutting methods 

 now, a lapse in production is unavoidable. In the 

 Deschutes River and the Klamath Plateau units, 

 the 1937-39 rate of cut from ponderosa pine 

 stand's exceeded their ultimate sustained-yield 

 capacity, attainable only after years of intensive 

 forestry, by substantial amounts. The 1937-39 

 cut was 63 percent greater than the ultimate in the 

 Deschutes River unit, 94 percent in the Klamath 

 Plateau unit. In other words in the latter unit, 

 the most important pine producer in the region, 

 the cut during these 3 years was nearly twice the 

 permanent productive capacity. 



Under a light selection system, the present allow- 

 able cut of ponderosa pine types in the Deschutes 

 River unit is only 2 percent lower than the ulti- 

 mate sustained-yield capacity; in the Klamath 

 Plateau unit it is 13 percent greater. This is due 

 to the fact that both units still contain a larger 

 timber volume than would be required (in younger 

 trees) to yield the total potential growth. 



Although the Klamath Plateau unit has a greater 

 volume than any other unit of the region, the 



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