16 Prolonging the Cut of Southern Pine 



stands. A study of the probable growth on this same area 

 indicated that if the stand were not cut, the growth in ten years 

 would amount to 3,299 feet b.m., or 36 per cent of the present 

 stand, making a total of 12,068 feet b.m. It thus appears that 

 in stands similar to those selected, nearly twice the actual volume 

 growth would be secured if the stand were not thinned than can 

 be expected after thinning. Owing to the greatly reduced 

 volume of the stand after thinning and the much greater average 

 growth of the remaining trees, compared with those removed, the 

 growth per cent, or ratio of growth to volume of stand on the 

 thinned or cut-over tract, is double the per cent growth secured 

 in the virgin stand. The stands selected represent those in good 

 condition for growth, and not those containing a surplus of over- 

 mature timber. A reduction in the number of trees to 40 per cent 

 of the former stand might be expected to reduce the growth in 

 the next decade, and usually does so. Only in "forties" of over- 

 mature timber is there apt to be a net increase in growth after 

 thinning, and this is due to elimination of loss from natural agen- 

 cies. Even then, a fair stand of young timber must be present, as 

 a basis for the second cut, to secure this result. 



It is important, therefore, to emphasize the real advantage 

 gained by leaving the smaller and thriftier trees for a second cut. 

 This lies, as indicated, in the very large increase in growth per 

 cent, obtained after thinning, upon the investment thus made. 

 The leaving of virgin timber, even when thrifty, involves an 

 investment measured by the volume, quality and stumpage value 

 of the stand. Clear cutting terminates this investment. The 

 growth in volume in virgin stands must be considered, not alone, 

 but in its relation to the existing volume of the stand in which 

 it is produced. While the growth in actual volume falls off as 

 the result of removing four-fifths of the stand, the growth per 

 cent of the remaining stand is twice what it was before the cutting. 



INCREASE IN VALUE OF SECOND CUT 



Seven per cent per year in volume does not represent the true 

 increase in value of these thinned stands. The lumber produced 

 from selected trees will be of high quality and value since they will 

 be freer from knots and other defects. If stumpage values 

 advance, this increase will be still greater. It is safe to count 

 on 10 per cent annual increase in value of properly marked 

 stands containing the requisite quantity of young timber after 

 cutting. These same stands would give scarcely 5 per cent 

 increase in value per year before they are cut over, most of 



