ZOOLOGICAL SOCIETY BULLETIN' 



The height varies from 150 to much over 225 

 feet, and as they are without taproots they stand 

 absolutely straight, often without branches from 

 the ground to a height of 175 feet. 



The crown usually is dead; not blasted by 

 lightning, .as lias been often stated, but because 

 ancient fires have eaten in at the base so that the 

 How of sup to the extreme crown has been 

 checked. When connection with the ground and 

 the life-giving water supply has been strongly 

 re-established, growth takes place from the top- 

 most uninjured branches, and forms a new but 

 false crown. It is estimated that if these trees 

 had escaped upsetting by the wind and had been 

 allowed to grow entirely free from fire through- 

 out their age long existence and had carried 

 their proportionate growth (calculated from the 

 tapering of the trunk) to their uttermost limits, 

 these giants would be 600 feet high. 



This is mere speculation, as is the theoretical 

 age of some of the more ancient trees. The 

 known age of trees which have been cut ii from 

 1. 100 to 3.250 years, but there is little doubt 

 that this long period is much exceeded in such 

 cases as the General Sherman tree or the Griz- 

 zly Giant. The life of these monsters can be 

 computed only by comparison with the measured 

 trunks of lumbered trees the actual age of which 

 has been ascertained from the rings of growth. 

 There is always a factor of uncertainty in the 

 size of trees depending on their rate of growth 

 and supply of water. In exposed positions with 

 poor water and soil, development may be greatly 

 retarded and a tree may be very ancient al- 

 though relatively small in size. On the other 

 hand, a favorable location, such as a pocket in 

 the rock or access to underlying water, might 

 greatly accelerate the growth of a tree within 

 the same grove. 



Some close observers claim that the size of 

 the annual ring increases with the dryness 

 and not with the moistness of the season. They 

 argue that there is little or no rainfall in the 

 Sierras during the summer and the ground 

 water comes from melted snow, that growth 

 takes place during the months when the ground 

 is free from snow, and that a wet season means 

 a heavy snowfall which lies around the trees 

 late in the spring and gathers again early in 

 the autumn, thus shortening the number of 

 weeks available for increase of bulk. 



If this theory be correct, then the series of 

 gradually thickening rings, culminating and 

 then thinning out again, which is characteristic 



The California State Highway in 1917— before cutting 



