28 A MILL SCALE STUDY OP WESTERN YELLOW PINE. 



.022e + .018/ + .01% + .018/1 + .007*' = Bvdl, value in dollars and 



cents of Bv, the .in- 

 termediate grade 

 lumber produced. 



.009 j + .011 A: + 015g = Cwd, value in dollars and cents 



of Cv, the low grade lum- 

 ber produced. 



Aval + Bval + Cval = B, value in dollars and cents per tree. 



i nnn T-? 



- = C, value per 1000 board feet per tree. . 



The above symbols are also used with a subscript "1" attached to 

 indicate similar relations for mature trees; with a subscript "1" and 

 prime attached, to indicate similar relations for butt logs of mature 

 trees; with a subscript "I 1 * and a double prime attached, to indicate 

 similar relations for top logs from mature trees. To illustrate : 



a stands for the average volume in board feet of C and Better 

 lumber contained in an immature tree D inches in diameter 

 breasthigh. 



of stands for the average volume in board feet of C and Better 



lumber contained in a 16' butt log from an immature tree 



D inches in diameter breasthigh. 

 a" stands for the average volume in board feet of C and Better 



lumber contained in the last log used from an immature tree 



D inches in diameter breasthigh. 

 !, a/, and a/' stand for similar relations for mature yellow pine. 



Symbols appear in lower right-hand corner of each diagram. 



FOR WHOLE TREES. 

 Age Identification Relations. 



Trees increase in diameter and height as they become older, and the 

 rate of increase is dependent upon a great many influencing factors not 

 always apparent to the closest observer. Trees of the same species may 

 have a wide range in rate of growth, such that the age can not be judged 

 by their size. It may be that the smallest tree in a group ranging in 

 size from twenty to forty inches in diameter breasthigh is the oldest of 

 that group, and the forty-inch tree the youngest. Some yellow pine 

 trees measuring over forty inches in diameter have proved to be less 

 than two hundred years old, whereas age determinations have shown 

 trees of half that diameter to be over four hundred years of age. 



The outward appearances of such trees are, however, very different. 

 The large ones which may be comparatively young have a dark, thick, 

 rough bark, numerous small limbs extending well down into the middle 

 third and a cone-shaped top, whereas the small ones, which may be 

 about twice as old, have a light colored rather thin, smooth bark, 

 furrowed longitudinally and horizontally, forming plates which are 

 comparatively smooth. All live limbs are very large and usually all 

 above the middle third. The top is generally dome-shaped. 



