Periodical Literature. 321 



It remains questionable whether by any analytical method it 

 would be possible accurately to describe the progress of growth. 



Zur mathematischen Interpretation der Zuzvachskurven. Allgemeine 

 Forst- u. Jagdzeitung. January, February, 191 1. Pp. 6-1 1; 48-59. 



The following curves constructed by 



Increment Kiinkele offer a convenient means for read- 



per cent. ing off the rate of growth in diameter, area 



Table. or volume, according to either Schneider's 



or Pressler's formula. Schneider's incre- 



200c 

 ment per cent, formula is p= — ry-, in which n, represents the 



number of rings per inch or other unit ; D, the diameter ; and c, a 

 coefficient which for diameter increment is=i, for area increment 

 =z2 ; for volume increment varies from 2 to 3 1/3, namely as fol- 

 lows: 

 when crozvn height growth 



finished moderate vigorous 



h 

 deep, to — , c= 2^ 2 2/3 3 



h 

 high, — , c= 22/3 3 31/3 



The ordinates give the increment per cent, with these various 

 values of c, the abscissae are based on the values of nD. Accord- 

 ing to their value they are read from the different style of num- 

 bers. Hence, only nD needs to be ascertained and the increment 

 per cent, may be immediately read off. 



1 00c 



The same curves correspond to Pressler's formula, p= , 



tiq 



in which n represents any number of rings, and q is the relation 



D 



, D being the present diameter without bark, and d the earlier 



diameter n years before. 



