470 TEANSACTIONS AND PROCEEDINGS OF THE [Sess. lvh. 



(/) Oak near, aud north of, Bewick's Oak, West Felton, 

 Salop (Mr. John Dovaston, in a letter to Sir R. Christison). 



(f/) Herne'.s oak, Windsor, 2G feet in girth when blown 

 down. On a block, 5 inches thick, of exterior decayed 

 wood, there were 142 rings; on the inner inch, 21^; on 

 the outer inch, 44 (Sir E. Christison). 



3. Estimation of Age in Ancient Oaks. 



We may form an approximate estimate of age in oaks 

 of very considerable size, but available data in the case 

 of the great " giants are so defective, and the difticulty of 

 estimating the period when they may have been " standing 

 still" in a state of decay is so great, that in them estimation 

 is little better than guess-work. Let us make the attempt, 

 however, on the Cowthorpe tree. 



The oldest oak on my list, with a well-ascertained age, 

 is the Baslow tree (1 /), whicli had 479 rings at a height 

 of 3 feet, and allowing G years for growth to that height, 

 must have been 485 years old. Its girth was 18 feet 

 3 in., and consequently its rate for the whole period was 

 0'46. Now the Cowthorpe oak is almost twice that girth, 

 and if we allow its rate to liave been 0'46 till it was 

 18 feet in girth, and take half that rate for the last 

 18 feet, its a^e, without any allowance for "standing still" 

 in the period of decay, comes out at about 1450 years. 

 IJut the Baslow tree was slow of growth, as one radius 

 increased at only half the rate of the other, and because 

 some of my trees yield a much liigher rate up to a con- 

 siderable size. Thus rates of 1*50 up to 40 years of age; 

 of 1-13 up to 71 ; of 1-19 up to 84; of 1 up to 86 ; of 

 0-86 up to 150; of 0-92 for 39 years in a tree 11 feet 



