206 Studies in Forestry [CHAP. ix. 



infectious nature, which may be obviated by timely and effective closure, 

 i. e. by antiseptic treatment.' 



And at another place he adds * : 



' In broad-leaved trees, especially the Oak, to which my investigations 

 have hitherto been confined, wounds over 4 to 4-8 inches in diameter, 

 should not be made.' 



The species of trees which best stand the removal of green 

 branches are the Oak, Silver Fir, Larch, and Pines, when they 

 are in energetic growth on favourable soil and situation and 

 have normally developed crowns. Ash, too, can well bear the 

 operation ; but, as Ash and Alder both grow with naturally clean 

 stems, pruning is hardly requisite in their case. Whenever the 

 removal of branches takes place to any great extent from Oak, 

 Maple, Sycamore, or Elm, the result is that the bole has a ten- 

 dency to become covered with shoots from the dormant buds. 

 This, of course, interferes very considerably with the technical 

 and financial value of the stem, besides, particularly in the case 

 of the Oak, exposing the tree to the danger of becoming ' stag- 

 headed' or dead in the upper portion of the crown. The soft- 

 woods Birch, Willows, and Poplars are not naturally adapted 

 for this kind of treatment, owing to the comparatively slight 

 resistance which their soft, porous wood is able to offer to the 

 development of fungoid disease ; hence any wound-surfaces 

 formed afford only too favourable a germinating-bed for the 

 disease-producing spores. 



In order to diminish the danger from fungoid diseases, it is 

 highly recommendable that the wounds should be coated over 

 with some antiseptic substance impervious to moisture. In 

 conifers this takes place naturally by the oozing out of resin ; 

 but some coating must be provided artificially in the case of 

 the broad-leaved genera. The tree-wax, formerly in general 

 demand for the purpose, consisted of a mixture of 1-20 parts 

 (by weight) of bees-wax, 2-70 parts of pure resin, 0-60 of tur- 

 pentine, 0-15 of wood-oil, and 0-15 of suet, all dissolved in 



1 Ibid. p. 228. 



