51 



* 100 . n 



so that/; = . = 1UO ( - + 



\^ hen there has been no increase in height, - 



_ 200 x diauietar increment 

 ' Actual diameter = ^ " 



Another simple formula to use is that of SCHNLIDKK, by which 



p = T- , D being the actual diameter in inche, exclusive of the 

 L)n 



bark, and the nnmber of annual rings in the last inch of growth. 

 2 

 - is obviously equal to one year's increase of diameter, and this 



ft 



figure can consequently be used in Breymann's formula above. 



Both Breymanu's and Schneider's formula give only the rate 

 of increase per cent, of the basal area, and the rate of increase 

 per cent, of volume must be obtained therefrom in different cases 

 as follows : 



(a) In the case of trees possessing vigorous upward growth 



and standing in a leaf-canopy, by multiplying by If. 



(b) In nearly all other cases of canopied trees, by multiplying 



by a factor varying from li to 1|. 



(c) In the case of isolated trees without any multiplication at 



all in many instances. 



E. Stem analysis, or the determination of the coorie of the increment of the 

 stem during the whole term o( it* life. 



If any tree forms annual rings, the observation of these ring* 

 enable us to trace its life-history, to say when it was suffering from 

 suppression, from insect ravages, from the effects of fire, frost 

 and from other retarding causes, when it enjoyed complete im- 

 munity from such injurious influences, and was a dominant 

 stem growing vigorously, and' so on. A longitudinal section 

 passing through every point of the axis of the stem would 

 show all this at a glance, but such a section is practically impos- 

 sible to make; the stem must be cut across into a number of sec- 

 tions, and the required information sought thereon. The sections 

 may be made at every 6 feet, but as a tree growt fastest 

 when young, the lower sections may be longer (up to 10 and 

 even 14 feet in the case of quick-growing trees), while the upper 

 ones may be made shorter. The first cross-cut should be made at 



