Rate of Gi^oivth in Old Trees 6 1 



The circumference of the shade is 76 yards. . . . 

 About forty or fifty years ago a portion, including 

 part of the trunk, fell out owing to the weight of 

 snow after a snowstorm.' 'Tradition would make it 

 nearly 900 hundred years old, and says that Brian 

 Boru, king of Ireland, died under it at the battle of 

 Clontarf, in which he defeated the Danes on Good 

 Friday, a.d. 10 14,' This would make it 983 years 

 old, while the girth is only 1 2 feet. 



Rate of Growth in Old Trees. — De Candolle 

 assumed that after a certain period the rate of 

 growth diminishes, and he accounts for this by 

 the greater distance of the roots from the air, 

 by their coming into contact with the roots of 

 other trees, or with a rocky or unsuitable soil, or 

 by the diminished elasticity of the bark. 



The trees on which his observations were 

 founded were evidently of unhealthy and stunted 

 growth, arising probably from defects of soil or 

 climate. His ideas, however, on the rate of orowth 

 have been adopted by most subsequent writers and 

 taken au pied de la lettre. But more extended ob- 

 servation and certain measurements of recent times 

 lead to the belief that these ideas and the inference 

 deduced from them are erroneous. It will be shown 

 presently that, as regards the yew especially, there 

 is ground for the assertion that not only does its 

 growth not diminish with age, but that on the 

 contrary it increases, on the whole, with a rapidity 



