78 



THE WOODSMAN S HANDBOOK. 



The method of computing the contents of a model acre or of any 

 sample acre depends upon whether or not height measurements 

 have been taken. If heights have been disregarded, the compu- 

 tation may be made in the following way : 



Make four columns of figures as shown in the accompanying form. 

 In the first column place the diameters, in the second column the 

 number of trees of each diameter, in the third column the average 

 contents of trees of different diameters, and in the fourth column 

 the total contents of all trees of each diameter, which is found by 

 multiplying together the values in the second and third columns. 

 The figures in the fourth column are then added together for the 

 total contents of the acre. 



Under ordinary circumstances a crew of 4 men should be able 

 to measure off 30 to 50 acres a day if only the merchantable timber 

 is included. In very open woods this number may be increased. 

 Where small trees are measured and special care is taken in laying 

 off the strips, 20 acres a day, or 2J miles of line, is about all that a 

 cruiser can measure. 



Form for computing the contents of sample plots. 



HEMLOCK. 



Diameter 

 breast-high. 



Number of 

 trees. 



Contents of 

 average tree 

 from vol- 

 ume table. 



Total con- 

 tents. 



Inches. 

 10 



10 



Board feet. 

 45 



Board feet. 

 450 



11 



11 



65 



715 



12 



9 



90 



810 



13 



8 



118 



944 



14 



8 



143 



1,144 



15 



9 



175 



1,575 



IG 



7 



205 



1,435 



17 



6 



240 



1,440 



18 



6 



275 



1,650 



10, 163 



