46 DETERMINATION OF THE CONTENTS OF STANDS 



method, in order best to compare them. Make no deduction for 

 defect or breakage and include all standing live or dead trees above 

 12 inches D.B.H. since the object of the exercise is to compare total 

 volumes. 



(a) Ocular estimate. 



Before measuring or counting any of the trees make an 

 estimate of the total volume of the tract. The succeeding 

 methods will show the accuracy of your estimate. Use 

 Form 1. 



(6) Commercial cruising method. 



Count all the trees on the tract, and estimate the volume 

 of the average tree. Multiply this volume by the number of 

 trees to secure the total volume of the stand. Check the 

 method by actual measurement of what is judged to be an 

 average tree, calipering its D.B.H., measuring the height 

 with the hypsometer, and computing the volume by the 

 Spaulding Rule of Thumb (See Problem 15, Illustration 1, 

 Method I). Use Form 1 for recording the measurements 

 and estimate. 



(c) D.B.H. volume table method. 



Caliper the diameter breast height outside the bark of all 

 trees on the tract. Compute the volume of the tract by use 

 of the volume table constructed in Problem 16, or any other 

 volume table based on diameters breast high only, which 

 would be applicable to the conditions. Use Form 3 A for 

 recording the measurements and estimate. 



(d) Diameter-height volume table. 



Cahper the diameters breast high outside the bark, and 

 estimate the total heights of all trees on the tract. As a 

 check measure with a hypsometer the heights of the first trees 

 taken. Compute the volume of the tract by use of the 

 volumes given in Tables V-VIII in the Appendix, or any 

 other tables based on D.B.H. and total heights that would be 

 applicable to the conditions. Use Form 4 for recording the 

 measurements. 



(e) Spaulding rule method. 



Tally the D.B.H. inside the bark and the length of all 

 trees on the tract from the breast height point to a point on 

 the bole where the D.B.H. is equal to h D.B.H. (outside 

 bark). Measure this length by means of a hypsometer. 

 Compute the volume of the tract by the Spaulding rule of 

 thumb explained in Problem 15, Illustration 1, Method I. 

 Use Form 3 A. 



