746 



JOURNAIv OF FORESTRY 



growth is justified. It has been observed that in some stands and some 

 locaUties, the presence of spiral grain is so large that stumpage values 

 are heavily depreciated. The production of trees with straight trunks 

 free from irregular and spiral grain will reflect to the credit of Amer- 

 ican silviculture by contributing very materially to the financial stability 

 of the rotation and by promoting economy in forest production. 



Fig. 4. — Composite curves showing the effect of spiral and diagonal grain on 

 modulus of rupture, modulus of elasticity, work to maximum load, and maximum 

 drop. White ash, Sitka spruce, and Douglas fir. 



