308 PRUNING. 



Though root-pruning is chiefly employed to check the luxuriance 

 of young fruit trees, and throw them into blossom, yet it may be 

 employed for these purposes with all trees and shrubs whatever, and 

 even with some kinds of herbaceous plants. The dahlia may be ren- 

 dered more productive in blossoms, either by ringing the stem just 

 above the root -stock, or by cutting through some of the main roots just 

 beneath it. The Chinese, it is well known, are celebrated for their 

 dwarf or miniature trees, and these are formed of the extremities of 

 the branches of very old trees, rooted by the process shown in fig. 189, 

 and afterwards planted in shallow pots in very poor soil, and as the 

 roots are produced, they are cut or burnt, so as to cramp the growth 

 to any degree required. 



Girdling and Felling. Girdling consists in the cutting out clean a 

 ring of the bark, about four inches in width, close to the ground ; 

 which, in larches, seems to cause the turpentine to be wholly incorpo- 

 rated in the wood, instead of passing down to the roots, and, in fact, it 

 so totally alters the condition of the trees, that the workmen complain 

 of their being much more difficult to saw. Another result appears also 

 very interesting. On February 9, 1831, a section was cut from a larch 

 that had been girdled, as above mentioned, in the spring of 1830, and 

 which then weighed 6540 grains. On March 21 it weighed 4990 

 grains, having lost 1550 grains. A similar section, cut at the same 

 time from an ungirdled larch, weighed on February 9, 5610 grains, 

 and, if it had lost by evaporation only in the same proportion as the 

 other, should have shown, when weighed on March 21, a loss not 

 greater than 1330 grains, instead of which, it then weighed only 3330 

 grains, thus showing a loss of 2280 grains, nearly double the propor- 

 tion of the former. The effect of this process in establishing the 

 straightness of the wood is, moreover, very beneficial. A ladder made 

 from a larch so treated will be useful, whilst one not so seasoned will 

 twist so as to be quite worthless. The testimony of a gentleman of 

 great experience is : " Before I girdled, I never could have a ladder 

 made of larch that would continue straight for a month ; but now I 

 nave them made durably perfect." The common Scotch fir is equally 

 improved by the girdling process. It prevents the wood from warping. 

 A door made of home-grown pine has stood in a very exposed place 

 as well as the best foreign deal. Girdling seems to change what 

 would otherwise be mere alburnum into timber resembling heart- 

 wond ; and this may be one reason why the boards made from such 

 trees are found not to warp. 



The Girdling Machine. Figure 260 will give some idea of the 

 girdling machine, a is a piece of wood two feet long, four inches 

 wide, and two inches thick, having two saws screwed on it, one on to 

 the top, and the other at the bottom, so as to be perfectly parallel at 

 the distance of six inches from each other, and projecting about three- _ 

 quarters of an inch ; b shows the uppermost saw ; c is another piece 

 of wood of the same dimensions, having four small rollers projecting 

 opposite to the saws ; d d show the uppermost two of these rollers ; 

 e is a slip of tempered steel, fixed to a at one end, and set to c at any 



