190 



TEAXSACTIOXS AMD PROCEEDINGS OF THE [Sess, lex. 



centuries may be assumed as a very probable age for the 

 Loudoun Castle yew. 



The rate of growth of two of the trees seems remarkable. 

 The Auchendrane birch is said to be only about seventy 

 years old. This will yield an annual girth-increase of 

 1'65 inch. The few birches I have observed do not grow 

 nearly so fast as this, and it is desirable that the alleged 

 age of the Ayrshire tree should be verified if possible. 

 The silver fir at Auchendrane is said to have been planted 

 in 1797, giving an annual rate of 1"88 inch, which, 

 although unusually high, I believe, is not unprecedented in 

 Scotland. 



To complete this view of remarkable Ayrshire trees, I 

 take the following examples of species, not included in Mr. 

 Paxton's book, from Mr. Landsborough's observations : — 



I cannot conclude without remarking how much the 

 value of Mr. Paxton's measurements would have been 

 enhanced had he been able to mark the trees at the 

 measured point. We should thus have been able in a very 

 few years to determine the probable, or at least possible, 

 rate of girth-increase in very large trees of the different 

 species, a point on which we have hardly any reliable 

 information. Unfortunately, it is not sufficient to record 

 in print the height above ground at which the girth was 

 taken without marking the place, because at a subsequent 

 observation the precise point may be missed, and a very 

 slight change in the position may yield very difiFerent 

 results, also because there is often a considerable differ- 

 ence of level in the ground at opposite sides of a 

 tree, so that even the approximate point of the recorded 

 girth is uncertain. Perhaps Mr. Paxtou may yet see 



