QUALITY OF TIMBER 167 



for common uses and it is the practice to cut down to normal 

 size most of the western coast lumber put on the market. 



The other tj-pes of timberland not listed above produce medium 

 sized trees with the exception of considerable spruce and lodge- 

 pole pine which comes on the market in small sizes. 



Technical defects vary with the use to which the trees are to 

 be put and the species. For example, less than 10 per cent of the 

 average eastern red spruce tree could be used for airplane stock 

 because only clear, straight grained wood would meet the require- 

 ments. On the other hand at least 60 per cent of a tree of the 

 same species can be used for pulp wood. Hence it is always neces- 

 sary in estimating the value of a tract of timber to be armed with 

 a full knowledge of the uses to which the trees are to be put 

 and what technical defects preclude them from such use. 

 This means that the estimator must know exactly what eflfect 

 knots, spiral grain, and color of sap wood or heartwood have on 

 the sale value of the species being valued. 



Closely related to the deductions for technical defects are 

 allowances made for damage from fire, insects, fungi, wind, snow- 

 break, noxious gases, etc. They are in fact determined in the 

 same way, by a close study of the cull made at the sawmill or 

 manufacturing plant. Usually it is not necessary or possible to 

 separate the effects of the different kinds of damage. Simply a 

 lump estimate of cull is sufl5cient. This may run from 60 per cent 

 of the log in the case of high grade quartered stock to less than 

 2 per cent in the case of boxboards. It must always be deter- 

 mined locally because use possibilities, amount and degree of 

 damage vary from tract to tract. 



The ideal to be attained in any logging operation is the most 

 complete utilization that market conditions will permit. This 

 should take into consideration not only the logs fit for lumber 

 but the whole tree. By volume an average tree is made up as 

 foUows: 



