PT. rv. 



PRUNING AND THINNING. 



221 



I think tliat the baobab should be ' restored to its 

 place in universal history,' because the next step taken 

 by physiologists on this datum of Adanson's will be, 

 that all trees of thirty feet in diameter are 5,150 years 

 of age ; and so, in proportion as the diameter of any 

 tree exceeds or falls short of thirty feet, an age greater 

 or less than 5,150 years will be assigned to it : from 

 which it would result that a tree must grow 174 years, 

 nearly two centuries, before it would attain one foot in 

 diameter. Lyell, speaking of a submarine forest at 

 Bournemouth, in Hampshire, says : ' Seventy-six rings 

 of annual growth were counted in a transverse section 

 of one of the buried trees, which was fourteen inches 

 in diameter.' This, though exceedingly slow growth, 

 is about three times the growth allowed by Adanson. 

 But were the rings perfect on each half diameter ? 

 If not, the width of those wanting on the deficient half 

 diameter must be added to the fourteen inches of 

 growth. On the other hand, and in accordance with 

 the rule above, we are told that De Candolle thinks 

 that the Montezuma cypress (Taxodium sempervirens) 

 at Mexico exceeds the age of the baobab, — exceeds 

 these poor 5,150 years in age. And this opinion is 

 quoted, with profound respect, by one of the most 

 profound men of the day, — by Lyell. Did De Can- 



"were half an incli, the growth in diameter wonld be an inch, and 

 the years and the inches of growth would be the same. That is, 

 the baobab would be 360 years old; allow half this growth, 

 which is perhaps fair, the tree would be 720 years old. (Third 

 edition.) 



