REGIONAL VOLUME TABLE 



731 



the graph at fir.st appears to be but a confused and meaningless tangle, 

 but on closer inspection, it will be seen that there are two rather well 

 defined types of curves, one concave upwards with its maximum at the 

 extreme left, and the other convex upward and with its maximum be- 

 tween 35 and 45 inches d. b. h. Furthermore, it will be found that the 

 former type is common to all groups with low maximum height and the 

 latter to those with high maximum height. The reason for this is ob- 

 scure. It appears that the curve form may depend on site quality, 

 though the data can hardly be considered adequate in amount to 

 prove this, and the reason therefore is obscure. Possibly the vary- 

 ing age of trees of a given diameter on different sites is the causal 

 factor, but investigation thereof was futile without a large number of 

 additional data. 



The following summary was the basis for determining how many 

 tables should be made and how the lines should be drawn between 

 them. 



Table 6.— Relation Betzveen Maximum Height and Frustum Form Factor. 



Locality 



Number 

 of trees 



Average Averisre 



form j form 

 quotient ; factor 



Maxim.um height 



Totrl, 

 feet 



Merchant- 

 able logs 



Smith Mill... 

 Deer Camp.., 



Group C 



Ellis Meadow 

 Group A 



Crocker 



Stanislaus II. 

 Stanislaus I . . 



Concave 

 Concave 



Concave 

 Straight 

 Convex 



Convex 

 Convex 

 Convex 



133 

 144 



148 

 157 

 168 



176 

 192 

 199 



It was finally decided to make the division indicated in this table, 

 thus defining 



Site I as stands in which tallest trees are 1 logs or more high. 



Site II as stands in which tallest trees are 8 or 9 logs high. 



Site III as stands in which tallest trees are 7 logs or under high. 



The group within each site were next combined to yield average 

 frustum form factors, from which curves were drawn. 



Table 7 gives the factors read therefrom. 



