710 LETTERS TO THE EDITOR. [I\Iar. 



The above certainly was a very fine tree, but I beg to inform 

 your readers who are interested in trees that there is one of the 

 same kind in Perthshire about double, the size of the Madderty one. 

 When Lord Mansfield acquired the estate of Logiealmond in 1842, 

 I measured the largest of a number of sycamore trees in Logie Den, 

 which then contained 309 cubic feet. 



Last week the bule was measured, and found to be 20 feet to the 

 first branch ; circumference at 5 feet from the ground, 12 feet 5 

 inches; average girth, 12 feet 3 inches. The bole contains 180 

 cubic feet; and the top above 20 feet measures about 160 cubic 

 feet of good sound timber ; — in all, the tree contains about 340 

 cubic feet of timber. William M'Corquodale. 



Jeanie Bank, Perth,, l^th February 1886. 



MECHANISM OF A TREK 



THE description of the mechanism of a tree may to some extent 

 explain its growth, but the analogies about the roots (as 

 human mouths and leaves as lungs) are too much strained to be of 

 much practical service to the forester, or even the scholar, who is 

 often obliged to accept his information from the pages of a book 

 instead of from the leaves of nature. 



The writer on this subject in the February number, says : " So in 

 a tree, the nourishment taken in at these tree mouths, the roots, 

 passes to the lungs (the leaves) of the tree, and there, by contact 

 with the air, is rendered fit to supply fresh material to the tree." 

 This description may fairly represent the mechanism of tree growth 

 in its normal state, but for practical commercial forestry we know 

 trees grow and thrive though deprived of their leaves, and in arid 

 soils live without the superflux of moisture from the roots to which 

 the writer in a previous part of his paper refers. The tea plants 

 live though denuded of their leaves. When a tree is cut down, and 

 shoots are sent up from the old root or bole, there are no leaves or 

 lungs to these shoots till they are some inches or even feet high, as 

 in the case of willows and osiers. 



For growing timber in great lengths for commercial purposes, all 

 lateral shoots are kept trimmed off, only the leading or top growth is 

 left. 



Many fine old trees in the ancestral parks of Britain were pollarded 

 on the Abbey and Nunnery lands to prevent the Commissioners of 

 Henry VIII. marking them as serviceable for the navy. They exist 

 to-day to prove that tree growth can be maintained irrespective of leaf 

 or lung sustenance for a season. J. Ciiaeles King. 



BuLSTEODE, Bucks. 



