VajHable Groivth 45 



is growing up through the fissures of the stem ; 

 so that I consider it too far gone to enumerate it 

 amongst the large trees still standing in the county 

 of Wicklow.' 



This shows the effect of a moist climate, and in 

 a measure helps to explain the disappearance of 

 old trees in Ireland — rapid decay following on 

 the mutilation, which in England would have pro- 

 duced a crop of young shoots from the trunk and 

 a rejuvenescence of the tree. 



The rate of growth in trees of several kinds 

 varies at different times, and it is found that the 

 number of annual rings represents a widely diver- 

 gent degree of growth. Thus De Candolle himself 

 counted the rings in several oaks, and found that 

 one which had attained the ao^e of two hundred 

 years had only the same circumference as another 

 that had reached fifty. It is well known also that 

 the rate of growth is not uniformly diminished, for 

 he found one oak of 333 years which had increased 

 as much between 320 and 330 as it had between 

 90 and 100. These observations on the oak apply 

 with equal force to the yew. It is not uncommon 

 in the latter to find the tree developing more on 

 one side than on the other, as is shown in a speci- 

 men in the Kew Museum, where 250 rings are 

 found on one side and 50 on the other. 



Comparing the number of annual rings with the 

 number of lines of radius, De Candolle considered 



