48 



A NATIONAL PLAN FOR AMERICAN FORESTRY 



fication by reason of a growth rate resulting from conscious effort 

 or otherwise. It may perhaps total 110 million acres. 



This area as shown in figure 21 would have to be raised to about 

 279 million acres by about 2000 A.D. to meet timber requirements 

 and to 339 million acres to insure full forest land use. The annual 

 increase in the area brought under extensive management during the 

 next 70 years would therefore have to be about 2% or 3% million 

 acres, depending upon the objective set up. 



Extensive management would produce an average of about 42 

 cubic feet per acre annually, or two thirds of the full forest yield to 

 be expected under intensive management. It represents a marked 

 advance over the estimated current average growth of 21 cubic feet 

 annually for the entire area of commercial forest land in the United 

 States. The growth for individual types and regions would have to 

 be increased from 50 to 200 percent. 



PRESENT AREA 



NEEDED TO MEET TIMBER REQUIREMENTS 



FOR FULL FOREST LAND USE 



60 



120 180 240 



MILLION ACRES 



300 



360 



FIGURE 21. To insure timber supplies adequate for national needs an area of 279 million acres should be 

 placed under extensive management during the next few decades; and to insure full land use an area of 

 339 million acres. 



Extensive management presupposes the levels of protection against 

 fire, insects, and diseases already outlined. It uses relatively simple 

 silvicultural methods such as the protection of advance reproduction, 

 the leaving of at least the trees which cannot be cut with profit, 

 additional seed trees where necessary, some attention to keeping the 

 better species in the stand, slash disposal, and the prevention of 

 injurious grazing. It places more emphasis on quantity than on 

 quality of production. It attempts at least a rough application of 

 the sustained yield principle. It would not ordinarily require plant- 

 ing or cultural measures in growing stands. It is characterized by 

 a minimum of effort and low costs which may actually in most 

 cases be found to be savings. 



It may in some cases be a necessary first step to intensive forestry. 

 Over large areas low in productivity or inaccessible to markets, it 

 may be the most desirable ultimate practice. 



