1 34 Studies in Forestry [CHAP. vi. 



crowns of trees. In these respects again, conifers suffer to 

 a far greater extent than broad-leaved genera, among which 

 Beech suffers more than Oak, Ash, Maples, or Elms. Of all 

 forest trees Spruce is, owing to the shallowness of its root- 

 system, most apt to become windfall ; whilst Scots Pine is, owing 

 to the brittleness or low degree of elasticity of its branches, 

 more apt to have its crown injured by violent winds or heavy 

 accumulations of snow or ice. A year seldom goes past 

 without the necessity of registering damage from one or other 

 of these causes ; though, fortunately, destructive storms like 

 the N.E. gale of November 17, 1893, in Scotland are rare. 



To prevent, so far as possible, damage from storms, Hess 1 

 recommends the admixture of deep-rooting species along 

 with those which have shallow root-systems, and adds that 



' The injuries caused by storms during the last decades should be 

 a warning to those sylviculturists who are over-eager to transform 

 forests of broad-leaved trees into coniferous woods ; such transforma- 

 tions should only take place when justified by extreme necessity,' 



as, for instance, when soils have become greatly deteriorated by 

 faulty treatment. 



Accumulations of snow on the crowns of trees become 

 diminished in mixed crops, especially when the conifers are inter- 

 spersed with broad-leaved trees. Besides allowing the snow 

 to reach the ground, the bare crowns of the latter afford some 

 slight support to the snow-laden crowns of the former. Even 

 when breakage results, it is then more of an individual nature, 

 and does not extend throughout large patches, or over the 

 whole of the crop as sometimes happens in Spruce and Pine 

 woods. Here again Hess lays down 2 , as the first sylvicultural 

 measure to be taken for the prevention of damage from snow 

 and ice : 



' The avoidance of the formation of pure forests of species liable to 

 suffer. Scots Pine is entirely out of place in such localities. So far as 



1 Op. cit., vol. ii., 1890, p. 287. 



2 Op. cit., vol. ii. p. 315. 



