YIELD TABLES 61 



It would have been more accurate to measure 

 a number of test trees for each major class in- 

 stead of only one ; but it was the aim to waste 

 as little timber as possible in the investigation. 

 Furthermore, this simple method is sufficiently 

 exact for every practical purpose. 



A careful description was made of the local- 

 ity of each valuation survey, and the following 

 points were noted : 



a. The relative and absolute altitude. 



h. The rock and soil. 



c. The condition of the humus. 



d. The surface growth. 



e. The quality of the locality, which was given 

 as I, II, or III, according as it was judged to be 

 good, intermediate, or poor for the growth of 

 White Pine. 



/. The density of the forest crop. This last 

 was expressed in decimals of 1. The density 

 was judged mainly by the forest canopy — that 

 is, if the cover was complete and the ground 

 entirely shaded, there being no holes or blanks, 

 the density was called 1. If there was only 

 half a crop it was called 0.5. The density of 

 White Pine and of all other species taken to- 

 gether was also determined independently. 



The diameter of the average tree of a group, 

 as we have seen, is found by dividing the total 



