512 TRANSACTIONS AND TROCEEDINGS OF THE [Sess. lvii. 



(/) Many in the Posso plantation, Tvveeddale, planted 

 1740, girthed 4 feet at 4 feet up, in 1767 ; rate, 1'77 for 

 twenty-seven years. A Scots fir at Bargaly, Kirkcud- 

 bright, eighty-three years old, girthed 9 feet 3 inches at 4 

 feet; rate, 1'33, and was 00 feet high (Dr. Walker). 



The possible rate of girth-increase in Scots firs of great 

 size in the primeval forests is established by the fortunate 

 preservation of the plank at Fochabers, by counting the 

 rings on which Sir R. Christison clearly proved that a tree 

 measuring probably 20, but certainly 19 feet in girth 6i 

 feet above ground, may attain that vast bulk in 272 years, 

 or at the rate of 0'84 inch annually. He also found that 

 although the rate varied in different decades, it was not 

 much, if at all, less towards the end than at the beginning 

 of the tree's career. This he attriluited to the unusual 

 height of the conoid base, but it is not likely that this 

 influence could be great so high as 6^ feet, and possibly 

 equality of the rings throughout life may be a true 

 characteristic of this and otlier species in exceptionally 

 vigorous specimens. 



The Dalswinton tree ('•) confirms Sir 11. Christison's 

 observation of the varialion in rate in different decades in 

 the Fochabers plank, as it grew very slowly from 1875 to 

 1888, and much more quickly from 1888^0 1893. The 

 great rate of the Hevvell Grange tree (c), 1-52, is con- 

 firmed by Dr. Walker's examples (/), and the five young 

 Dalswinton ones (d). 



II. TllK Ykw (Ta.'-us J)arr(it((). 



The general rule of measuring at 5 feet from the ground 

 is inapplicable to this species, because of its various habits 

 of growth. Some aged yews are buttressed like other 

 large trees, but this is exceptional. Others are cylindrical 

 from the ground, and change but little in girth till the 

 branches are given ofi'; in most* of this class the stem is 

 short, but in rare instances, unknown 1 believe in Scot- 

 land, it is long, like that of a pine tree. ]>ut frequently, 

 in aged yews, the stem is luurowest at the ground, and 

 swells rapidly to the offslioot of tlie branches, only a few 

 feet from the ground. Hence, for comparison by a single 



