34 On the Longevity of the Yew. 



average of 36% rings per inch ; the average of both being 4 i 

 rings per inch, very nearly. Therefore this yew, with a mean 

 diameter of 9 ft. 5 in., or radius of 4 ft. 8 J in., would consist 

 of 2186 concentric rings or annual zones. Making the same 

 deductions I have done in the Gresford yew for more rapid 

 growth during the first 246 years, its present age will be 

 about 2006 years. 



The result of this examination of the sections shows the 

 Gresford tree to be about 200 years, and the Darley one 

 about 650 years, older than the method of allowing a year for 

 each line of the diameter would indicate. It also shows that 

 the latter, with a mean diameter of only 11 in. more than the 

 former, is 587 years older, the difference arising from the 

 greater thinness of its annual rings. This discrepancy could 

 never have been detected without resorting to actual sections; 

 and in this instance it may be owing to the Darley yew having 

 fewer branches and less luxuriant foliage, in consequence, 

 possibly, of its roots having been constantly mutilated by new- 

 made graves ; a custom that ought not to be allowed. A thin- 

 ner circle may also be caused by poverty of soil, lack of 

 moisture, coldness of climate, or partial exclusion from air 

 and light; for, where any of these operate, I suspect we shall 

 always find a corresponding diminution of woody deposit. 

 Even the plan of taking horizontal sections is liable, in the 

 yew at least, to lead to great errors unless caution be used, 

 and several sections be obtained. This arises from the great 

 and constantly recurring inequality in the thickness and paral- 

 lelism of the rings, both individually and collectively. This 

 general character of the wood is probably the cause of the 

 many prominences and recesses in the boles of old yews. The 

 same ring is often two or three times thicker or thinner in a 

 given point of the circle than in a neighbouring part; and a 

 series or fascicle of rings will often alternately swell or di- 

 minish together, while other series, both older and younger, 

 will be thickest where the first were thinnest, and vice versa. 

 This arrangement gives to their cross section an undulatory 

 appearance, so beautiful in the polished wood, especially where 

 the zones are deposited irregularly by the protrusion of branch- 

 lets from the trunk. It also causes a line drawn across the 

 section in the direction of the radius, to facilitate the counting 

 of the rings, to pass so obliquely through some of them, that 

 they appear to have two or three times their real thickness ; 

 and makes it dangerous, where calculations are to be founded 

 upon it, to trust to a single section. It is also necessary to 

 count the number contained in an inch, in as many portions 

 of the same section as possible, and then to strike a general 



