230 A NATIONAL PLAN FOR AMERICAN FORESTRY 



stands, which keeps actual growth of saw timber at a low figure. 

 Even on the basis of the smaller regulated growing stock assumed in 

 the second column a sustained yield of more than two thirds of the 

 1925-29 saw-timber drain could be maintained. 



Regulated growing stock with saw-timber volumes equal to the 

 present volumes (column 1) in that great Lake-Central-South belt 

 would be adequate to maintain about one third of the 1925-29 saw- 

 timber drain. This disparity would be further increased with the 

 smaller growing stocks under the other two assumptions. 



The sustained-yield possibilities indicated for the western regions have 

 little significance because of the abnormally large volumes of over- 

 mature timber now present. It is obvious that the true sustained-yield 

 possibility of the western regions is less than that indicated in the first 

 column and perhaps even less than that indicated by the calculated 

 1950 growing stocks (column 3). Although it is believed that a great 

 many years will elapse before all of the more remote and otherwise less 

 desirable stands become economically available, it is probable that 

 as time passes, the margin of accessibility will be extended. 



These calculations, as previously implied, are useful in giving a 

 proper perspective to the existing growing stock situation from the 

 standpoint of sustained yield. As a matter of fact, the situation is 

 somewhat less favorable than might be implied from the figures alone. 

 Individual properties or localities within regions are, as a rule, not 

 characterized by the regular distribution of age classes needed for 

 sustained yield in keeping with actual stand volumes. Such distribu- 

 tion of age classes may not exist even for the region as a whole. 

 Moreover, heavy depletion is actually taking place quite generally 

 in the cordwood and second-growth saw-timber stands below 

 rotation age. 



It remains to consider sustained yields which might be obtained 

 under some combination of intensive forestry, extensive forestry, and 

 simple protection against fire. It is believed that the play of economic 

 forces will lead to the practice of intensive forestry on the most 

 favorable situations before anything more than fire protection will 

 be economically justifiable upon the poorer and more remote lands. 

 At the same time, because of ownership or other factors, certain lands 

 will be given little, if any, forestry treatment even though physically 

 and economically suited to it. Some combination of extensive and 

 intensive forestry, however, appears to be closer to the probable 

 realities than would a premise which involved only extensive forestry 

 or only intensive forestry. The relative acreages assumed for each 

 type are in no sense forecasts of what will happen. 



For this discussion simple protection means a degree of protection 

 which will prevent fires from causing a serious drain at any time. 



Extensive forestry embraces fire protection as just defined, and 

 such cutting practices or simple silvicultural measures as are necessary 

 to maintain production in sufficient quantity for commercial utiliza- 

 tion. It would include, as occasion requires, such measures as defer- 

 ring cutting until reproduction has become established, slash disposal 

 as an aid in fire protection, the preservation of advance reproduction, 

 the leaving of seed trees, prevention of overgrazing, and girdling cull 

 hardwoods to permit valuable young growth to develop. It will not 

 ordinarily include planting. 



Intensive forestry is used to include a very high degree of protection 

 against fire, insects, and disease. In addition, it will require cutting 



