30 



60 70 #0 JO /CO 



per acre 

 CjOOO c.jJ 



H. 



H/ta 



7ooo 

 6ooo 



Sooo 

 i 



^000 



H50- 



s 



s 



\ 



yFig. 4. Spruce; Middle and North Germany; Sites I-V; Normal Yield of 

 Main Stand in cubic ft per acre. Also the points indicating at what age the average 

 tree attains a diameter of 8", 10" and 12", and a height of 40 ft, 50 ft, etc. Only 

 wood 3" and over is here considered. 



153 



