328 Forestry Quarterly. 



SILVICULTURE, PROTECTION AND EXTENSION. 



In 1905 and 1906 Oberforster Haak, an ex- 

 Germination pert in this line, published investigations 

 Per Cent. (see Quarterly, Vol. V, p. 205) into the 



and relations of the germination per cent, of 



Seed pine seed to the number of plants actually 



Storage. resulting, which showed that the use value 



of seed increases and decreases with increas- 

 ing or decreasing germination per cent, in much more rapid pro- 

 gression than the final number of germinated seeds in a test would 

 indicate. To secure the same number of plants, very much less 

 seed of a high germination per cent, is required than proportion- 

 ately of seed of a lower per cent., i. e., lower grade seed is much 

 less valuable than its germination per cent, indicates. 



To secure more precise data on this relationship, to determine 

 what the author calls the "plant per cent." corresponding to a cer- 

 tain germination per cent., some 129 sowings in seedbed and in the 

 open were made with 400 to 800 grains to the sowing, and the 

 number of resulting plants counted. To take account of the dif- 

 ference of seedbed, practically experienced, three different condi- 

 tions, favorable, unfavorable and half- favorable, were created. 

 From the curves representing the results the following relation- 

 ships were deduced : 



Germination per cents. : 50 55 60 65 70 75 80 85 90 95 

 Plant per cents. : 



I Under favorable conditions 11 15 20 25 30 35 41 47 54 61 



II Under unfavorable conditions 2 4 7 9 12 16 20 27 



III Under half-favorable conditions 2 7 11 17 22 28 34 41 48 56 



VI Average of I and II 5 7 11 14 18 22 26 31 37 44 



While under favorable conditions seed of 60 per cent, germina- 

 tion will furnish one-third the number of plants indicated by its 

 germination per cent., a 90 per cent, seed will furnish 54, more 

 than one-half the theoretical figure. Since there are so many in- 

 fluences at work to make conditions favorable or unfavorable, the 

 author proposes the use of the figures which result from averaging 

 the figures under I and II, and which he finds to agree very well 

 with the best practice. 



To explain the strikingly lawful progress of the decrease 

 of plant per cent, with decreasing germination per cent., 



