SCHNEIDER'S FORMULA FOR STANDING TREES 431 



Further modifications of this formula are discussed in Graves' Mensuration, pp. 

 306-7. 



330. Schneider's Formula for Standing Trees. The most con- 

 venient formula for testing the growth per cent of standing trees is 

 known as Schneider's formula, developed in 1853 by Professor Schneider, 

 Eberswalde. This formula is applied at B.H. and requires the deter- 

 mination of diameter, D, at that point, and the number of rings in the 

 last inch of radius, n. Then 



400 



The following description of the derivation of the formula is taken from Graves' 

 Mensuration, p. 308. 



If n represents the number of rings in the last inch of radius at breast-height, 



then the periodic annual growth during n years is - inches. Let the present diameter 



n 



2 

 be represented by D, then the diameter last year was D — and the diameter at the 



n 



2 

 end of one year from now will be D+— . 



n 



vD*hf 

 The present volume of the tree is — - — , that of one year ago was 



2\ 2 

 D ~ n) * 



n 

 \ n/ 4 \ n n 1 / 



TrD 2 hf Trhf/4D 4\ 



%: — I 1 = J 



4 \ n n*J 



4 



The growth for the last year is then 



xfl'ftf r 

 4 _ 4 



The growth per cent is: 



*n*hf Trhf/iD 4\ 



= 100: p. 



4 



400 400 

 P ~ nD~n 2 D*' 



2 2 



If the growth be calculated on the basis of d-\ — instead of d — , then the follow- 



n n 



ing formula will result: 



400 400 



P ~nD nW* 



The average between the two formula is taken, namely, 



400 

 V ~nD' 



Inasmuch as Schneider's formula assumes that there is no change 

 in height and nor change in form factor, the results are very conservative. 



