IIO THE DARLEY YEW. 



increase would have been a foot in diameter in 60 years, and an 

 inch in five years ; and the annual increase would have been a 

 tenth of an inch. It may be that the yew took 600 years to 

 attain a diameter of 10 feet; but I entertain considerable doubt 

 whether it was so long, and the more so, as the oldest Clysthydon 

 yew has increased at least two feet in 100 years, which strongly 

 tends to show that this yew might have attained 10 feet in 

 diameter in 500 years. 



Generally, very large trees have grown as much more rapidly 

 than others of the same species, as they exceed them in size. It 

 is only necessary to look at any wood or plantation where all the 

 trees were planted at the same time, to be convinced of this fact ; 

 for there the largest trees must have grown the fastest. And, 

 although it is quite true that the longer a tree may continue 

 growing, the larger it will become, still it may well be doubted 

 whether such remarkable trees as the Darley yew could ever have 

 grown slowly in their earlier years. 



The increase of a tree in girth is caused by the sap, which 

 annually ascends to feed the leaves, and the quantity of sap that 

 ascends is greater or less in proportion to the quantity of foliage 

 on the tree, and the foliage is the greatest wherever the tree 

 stands in the open, so that it can spread its branches in every 

 direction uninterruptedly, and hence it is that the increase in girth 

 is greatest where the tree stands in the open, which is the case 

 both with the Darley and Clysthydon yews. Generally, a tree 

 increases regularly until it reaches a point which may be called its 

 best, and the head of the tree then generally continues for some 

 time nearly stationary, and then gradually dies away. As long as 

 the tree continues stationary, the same quantity of sap ascends, 

 and the same increase in girth occurs. But as the foliage 

 diminishes, so does the sap and the increase in the girth. The 

 Clysthydon yews have none of them reached their best ; but the 

 Darley yew seems to have done so. It still, however, bears a 

 very large quantity of foliage, and that shows that its girth 

 continues to increase, and this is put beyond a doubt by Mr. 



