DETERMINATION OF INCREMENT OF TREES BY STEM ANALYSIS. 243 



The following table gives the volume of the stem of the 

 tree at different ages. As the thickness of bark at former 

 periods cannot be ascertained, the calculations can refer 

 only to the increment of wood, exclusive of bark. 



Age, 



Total Timber, 





Tears. 



Cubic feet. 





6Q 



86-50 



Whole tree including bark. 



66 



74-65 



Whole tree without bark, 



56 



62-67 





46 



44-93 





36 



26-87 





26 



11-72 





16 



3-34 





6 



0-30 







12-92 



Top of tree considered as a cone. 



By graphically representing the volume of the wood at 

 the several ages, Fig. 3 is obtained, which with the pre- 

 vious diagrams, gives the following data : — 



Age of 



Height 



Diamet?r with- 



Volume without 



Periodic incre- 



tree in 



in 



out bark at 5 ft. 



bark, in cubic 



ment for every 10 



years. 



feet. 



from ground, in. 



feet. 



years, cubic feet. 













} i 



10 



33 



3-7 



1 



} • 



20 



55 



6-8 



6 











30 



76 



9-6 



16 











| ,9 



} » ' 



40 



90 



12-2 



35 











50 



100 



15 



53 











60 



106 



17-4 



68 











[ Q-Q 



66 



107 



18-2 



74-6 



\ 



Fig. 4 is a graphic representation of the current annual 

 and the mean annual increment of the volume. 



The current annual increment rises rapidly after the first 

 youth of the tree is passed and reaches its maximum about 



