302 



Sierra Club Bulletin 



gion — namely, these junipers. Barring extraordinary acci- 

 dents, the curve of their growth should be essentially like that 

 of the sequoia, having the same time-scale, and differing only 

 in the scale of magnitude — that is, the ordinates of the juniper 

 curve should at all points be proportional to those of the se- 

 quoia curve. The problem is therefore to find the constant ra- 

 tio between the two. 

















































f 







































































































































































































































































































































































































































































































































































































































































































u 























































































































































































































2 





T 



T 



T 



woo 



1 



13 



w 



M 



M 



16 



M 



le 



IK> 



1000 











00 









So 00 











Turning now to the first juniper of the above list, we see that 

 the initial point of its curve must of course be at zero of the 

 century scale. A second point is also known, determined by 

 its age of 247 years (at P) and its diameter of 24 inches (Pa). 

 By continuing the vertical coordinate Pa to the sequoia curve 

 at d, we get the ordinate of that curve at the 247-year point Pa, 

 — that is, the radius-measurement of the sequoia at that age, 

 29.5 or 0.8 is therefore the ratio sought. Applying this ratio 

 in succession to each of the 200-year measurements of the se- 

 quoia growth, we shall have the corresponding measurements 

 of our juniper according to our forecast, which, when plotted, 

 give us curve No. 2 of the chart. In like manner the age and 

 measurements of the Glen Alpine tree result in curve No. 3 of 

 the chart. 



The scheme assumes that by the time such a tree as these has 

 reached the age, say of 250 years, it has struck its true pace — 

 has found its proper scale of growth. Forecasting on this basis 

 the "expectation of growth" for these two trees, we find that 

 the mountain juniper might attain the five feet of diameter as- 

 signed to its class at about the age of 1300 years, and the val- 

 ley juniper the seven feet assigned to its class at about 1500. 

 The forecast is probably a little too favorable for the junipers 



