200 The Farm Woodlot 



by referring all the trees in the stand table to the proper 

 volume tables, we are able to obtain the total volume of 

 all the trees on the average acre. This is called a yield 

 table and from it the farmer is able to tell the exact 

 amount of lumber that his tract will cut, how much the 

 yield will be if he takes out only the trees above a certain 

 diameter, and what will be left for future cuts. 



CRUISING METHODS 



There are almost numberless methods of estimating 

 timber by ocular estimate, or " cruising, " as it is commonly 

 called; but only two or three that are applicable to the 

 woodlot will be taken up here. The results of the esti- 

 mating is worked out in board feet, but the unit measure 

 in the field is the log. The number of logs of different 

 species, lengths and diameters are recorded on a tally 

 sheet and the results worked out in the office. The diame- 

 ter should always be estimated at the small end and in-, 

 side the bark, since that is where the scale is applied. 

 The diameter at the large end does not make any dif- 

 ference. 



In order to do this work accurately, the eye must be 

 trained to two things, the estimating of diameters at a dis- 

 tance, and the estimating of heights. The first may be 

 secured by the use of tree calipers, which the beginner 

 should always carry with him. He should estimate the 

 diameter of every tree and then check it up by the use of 

 the calipers. By doing his estimating at different distances 

 from the tree, he can learn what the different diameters 

 will look like at varying heights on the tree. The eye 

 quickly becomes trained to this work, and in a short time 



