16 



BULLETIN 863, U. S. DEPARTMENT OF AGRICULTURE 



ber contents is found by referring to a copy of some log rule; prob- 

 ably the most common rule in use is the Doyle, although for small 

 logs under 16 to 20 inches it is very inaccurate, because from one- 

 third to one-half more lumber is usually sawed out than is indicated 

 by the rule. (See Supplement, p. 37.) 



How bolts and billets are measured. What makes a standard 

 cord of wood ? 



Allowances made for defects in saw logs, bolts, or blocks, and in 

 other material. 



Estimating standing trees: Finding approximately the contents of 



standing trees in cords or 



board feet of lumber by 

 measuring the diameter at 

 breast height (4J^ feet 

 above the ground), estimat- 

 ing or measuring the num- 

 ber of 16-foot log cuts in the 

 tree, and by the information 

 given in Farmers' Bulletin 

 1210. Find the merchant- 

 able contents of the tree 

 expressed in board feet. 



Estimating whole woods : 

 Applying the same method 

 to all the trees on a meas- 

 ured one-tenth or one- 

 quarter acre, and thereby 

 estimating th e contents 

 per acre. Recording the 

 measurements by different 

 species on a simple blank 

 form ruled in squares in 

 two directions. 



Practical exercises. — This 

 lesson should be essentially 

 one of practice. The class 

 should measure logs ac- 

 cording to the Doyle rule, 

 standing trees by the use of 

 volume tables for trees, and 

 cordwood by dimensions of 

 the piles. A good exercise for the more advanced students is to make 

 estimates on logs and standing trees and then by applying the Doyle 

 rule or the volume table test the accuracy of the estimates. The 

 practical value of this lesson is in acquainting the pupils with com- 

 paratively easy ways by which they can measure logs and cordwood 

 and estimate the amount of lumber or cordwood in trees. 



Correlations. — The operations mentioned in the practical exercises 

 will afford abundant work in calculations and suggest a varied list 

 of arithmetic problems. 



Fig. 9. — Measuring and estimating the saw timber in a 

 stand of short-leaf pine 



