CHAPTER V 



Causes of variation in growth Retardation and acceleration Pol- 

 lardingits meaning Frequency Causes Results Rings of 

 wood Hollow trunks becoming solid. 



THE rate of growth in yew-trees is very variable, 

 at one time becoming so slow as to seem, to the 

 ordinary observer, altogether arrested ; at another 

 period growing with a rapidity far beyond that of 

 the usual rate of increase. 



All the conditions which conduce to variation 

 require somewhat minute consideration before we 

 can arrive at an approximate idea and all esti- 

 mates of this kind can only be approximate of the 

 age of any of these trees. 



First, then, of 



Pollards. The conditions on which pollarding 

 depend are of several kinds, but a word or two 

 is necessary as to the meaning of the term ' pol- 

 lard,' which, in the case of the yew-tree, must be 

 taken to mean the breakage, or cutting, or even 

 the bending, of the leading shoot. Bacon says : 

 * Nothing procureth the lasting of trees so much 

 as often cutting ; and we see all overgrown trees 



