80 SEEDING AND PLANTING 



is true of some of the virgin forests of Washington and Oregon 

 where seed trees, when left, are practically a total loss, since they 

 cannot be harvested economically after the regeneration has been 

 attained and are not likely to remain sound until the end of the 

 second rotation. 



The cost of artificial regeneration varies between wide limits. 

 Successful stands have been attained at a cost of $4 per acre, 

 while sometimes they have cost $50 or even more. The average 

 cost in the United States is between $8 and $15 per acre. In 

 our overmature stands, the seed trees left standing may be worth 

 more than the cost of artificial regeneration. 



3. The Time Required for Natural as Compared with 

 Artificial Regeneration 



In artificial regeneration the new crop is started shortly before 

 or immediately after the removal of the old stand. The trees are 

 all started at the same time, and it is only in cases where blanks 

 occur in the first seeding or planting that a second or third year 

 is required to complete the regeneration. On the other hand, 

 in natural regeneration it is seldom that a single year will suffice 

 to attain a full stand. It is only under exceptional conditions 

 that it is attained in less than 10 years, and sometimes it is 20 or 

 even 40 years. When the period of natural regeneration is 20 

 years or less, the resulting stand is usually considered and handled 

 as an even-aged stand. 



4. Variation in the Character of the Stand Arising from 

 Natural as Compared with Artificial Regeneration 



In recent years, there has been much controversy in Europe re- 

 garding the effect of artificial regeneration, particularly planting, 

 in reducing the vitality of the stand when handled under a long 

 rotation. It is generally acknowledged that the artificial stand 

 as compared with the natural is more quickly established and 

 more uniform in distribution and in the size of the individual 

 trees. The growth during curly life is also more rapid. It 

 appears, however, that it is more sensitive to external harmful 

 influences and that the trees begin to fail or fall off in increment 

 at an earlier age than in stands that have arisen from natural 

 seeding. The contention is made that in the artificially estab- 

 lished forest the trees are usually of the same age and in pure 



