io6 



SILVER PINE TYPE 



are two storied with the pine always on top. Stands may be 

 divided by their composition into the following groups or sub- 

 types: 



Stands per acre 



Pure silver pine 100,000 board feet maximum, 30,000 board feet average 



Pine and red cedar 200,000 board feet maximum, 50,000 board feet average 



Pine and hemlock 200,000 board feet maximum, 50,000 board feet average 



Growth conditions for silver pine on good sites may 

 marized as follows: 



be sum- 



These figures are simply estimates since there are unfortunately 

 no accurate measurements for the tree species in this type. 



Damage may be either negligible or very severe. Fires, for 

 example, can ordinarily do little harm in the type because the 

 stands are so dense as to keep the ground cover moist except in 

 times of long continued dry weather. But when the woods do 

 dry out a fire that starts on the ground quickly becomes a top fire 

 and kills the entire stand. Hence, the damage is appalhng in a 

 serious drought. For example, the fires of 1910 in northern 

 Idaho killed outright thousands of acres of silver pine. 



While there are species of insects which attack the silver 

 pine none of them have so far been reported in large numbers. 

 Three fungi, Trametes pini, Polyporus schweinitzii and Fomes 

 annosus have, however, been found to cause a large amount of 

 heart rot. In the Cceur d'Alene region of Idaho investigation 

 showed 7 per cent of the volume of the stand affected by these 

 fungi. These studies by Weir and Hubert (U. S. Dept. of Agr., 

 Bui. 799) covered 1400 trees oh sevep National Forest sale areas. 



Timber Values. — In this type as with eastern white pine the 

 high value of the timber makes an intensive estimate necessary 

 so that the cost is high in spite of the easy topography and uni- 

 formity of composition. In fact, nothing less than a 10 per cent 



