ESTIMATING THE VOLUME. 69 



The best shape would be that which includes the greatest 

 area, as compared with the boundary, in other words a circle. 

 As this is impracticable, it is usual to give to the sample plot 

 the shape of a square, or of a rectangle approaching a square. 



4. Measurement of Volume on Sample Plots. 



This can be done according to any one of the methods 

 described above. As here a conclusion is drawn from the 

 volume of a small area to that of the whole wood, it is desir- 

 able to measure the volume on the sample plot as accurately 

 as possible. 



5. Merits of the Method of Sample Plots. 



The method of sample plots works quickly, and it affords a 

 great saving of time and expense as compared with the measure- 

 ment of whole woods. On the other hand, its accuracy depends 

 on the degree to which the sample plot represents an average of 

 the whole wood. Hence, it only yields accurate results in regular 

 grown young and middle-aged woods, less so in old irregularly 

 stocked areas, or where the quality changes frequently. The 

 method is chiefly useful where very extensive areas have to 

 be assessed, or where the value of produce is small, in fact 

 where a high degree of accuracy is either impossible to attain, 

 or not required. Where only small areas have to be measured, 

 or where the value of a forest has to be ascertained for the pur- 

 pose of sale, in fact where a high degree of accuracy is wanted, 

 the whole wood should be measured. 



SECTION III. DETERMINATION OF VOLUME BY ESTIMATE. 



Instead of measuring the trees on the whole or a part of the 

 area, the volume can be estimated in various ways, of which the 

 following deserve to be mentioned : 



