562 JOURNAL OF FORESTRY 



tion of site qualities. The determination of site quality is done as 

 follows : 



The height and diameter of the tree are determined. Locating the 

 diameter of the tree on the abscissa of his site quality graph and the 

 height of the tree on the ordinate, the estimator runs up from the 

 diameter and across from the height, and that site quality curve which 

 is nearest to the intersection of the two coordinates is the site quality of 

 the area. 



A sample graph is illustrated on page 5(Jl. 



The instructions on the reverse of the graph are as follows: 



TO THE ESTIMATOR 



You have detemiined the height and D.B.H. of the tree, 

 To Find the site quaHty : 



If the tree is over 30 inches D.B.H. then — 



Site I — Trees over 160 feet tall; 



Site II— Trees between 135 and 160 feet tall; 



Site III— Trees between 110 and 135 feet tall; 



Site IV— Trees under 110 feet tall. 



If the tree is between 8 inches and 30 inches D.B.H. then — 

 Run up on the diameter ordinate, and 

 Across on height abscissa, and 

 The intersection is the site quality. 

 If the intersection falls : 



Above Curve F the site is I, 



Between F and D the site is II, 



Between B and D the site is III, 



Below Curve B the site quality is IV. 



If the diameter of the tree is less than 8 inches, then the site quality is deter- 

 mined by analogy, using topography, soil, moisture, general health and 

 growth of the trees. 



In determinations always use thrifty, uninjured, dominant or co-dominant 

 trees, preferably not growing in dense stands. 



It is believed that after two weeks of the work the estimator will 

 be able to determine the site quality with as little mental effort as he 

 uses in determining the number of logs per tree. 



On the estimate sheet should be printed a diagram which is divided 

 into either two or four parts, depending upon whether the cruise is 5 

 per cent or 10 per cent (if 5 per cent, the diagram is divided into two 

 parts; if 10 per cent into four parts). This diagram represents the 

 forty being cruised. When the estimator arrives at the end of the 

 forty (or division of forty) he glances over the heights and diameters 

 which he has obtained, uses his graph to determine the site quality of 

 the area covered, and records in the proper part of the diagram the site 

 quality — I, II, III, or IV, as the case may be. 



