Practical Sylviculture 139 



wood is a part of the woody stem. The large amount of 

 ash from the cigar shows the amount of fertility drawn 

 from the soil. The comparatively small amount of ash 



FIG. 38. Greatly in need of thinning. 



from the piece of wood indicates what the tree obtained 

 from the soil and stored in the wood. Tree leaves contain 

 about as much ash as tobacco leaves, but the tree returns 



