110 THE PRINCIPLES OF HANDLING WOODLANDS 



operation, and a loss of interest on their value during the 

 period of reproduction. This may be compensated by 

 increase in market value, and in some cases by the growth. 

 If one cannot return for the seed-trees after reproduc- 

 tion is secured, and if the seed-trees are necessarily old 

 and mature, it is probable that they will not live until 

 the new stand is ready for cutting. The trees are then 

 sacrificed for reproduction, and their value represents 

 the principal item of investment for that purpose. It is 

 obvious that one may leave better trees, and more of 

 them, in the first than in the second case. 



NUMBER OF SEED-TREES. This depends on a variety 

 of conditions. There must, in the first place, be enough 

 trees to secure an abundant distribution of seed. Ordi- 

 narily the principle is to leave just as few trees as possi- 

 ble. This is especially important when it is likely that 

 the trees will not be utilized by a second cutting. The 

 forester determines the required number by a local study 

 of reproduction. He determines how far abundant seed- 

 ing will take place from individual trees of the species 

 in question, taking into consideration their height and 

 crown development, as well as the conditions of site and 

 exposure to wind. The conditions of germination must 

 also be considered; for, where these are not favorable, a 

 larger number of seed-trees should be left than under 

 the better conditions. 



In general, the seed-trees should stand not farther 

 apart than their average height. Under the best condi- 

 tions, they may sometimes be reduced to an average of 



