36 PROTECTION OF WOODLANDS. 



23. Factors determining the Nature and Extent of the Damage. 



The occurrence of damage from storms, and the nature and the 

 extent of the injury done, are dependent on many factors and 

 influences. 



The species of tree is, on the whole, the factor of greatest 

 importance. The ever-green conifers Spruce, Silver Fir, and 

 Pine retaining their foliage throughout the winter, and offering 

 a much larger extent of surface to the violent winds that occur 

 chiefly between the late autumn and the following spring, suffer 

 damage to a far greater extent than the Larch and the broad- 

 leaved trees which are then defoliated. And of these three 

 ever-green conifers, Spruce is most exposed to danger, owing to its 

 dense foliage and its shallow root-system ; whilst the equally 

 densely-foliaged Silver Fir is better protected by its deeper root- 

 system, and, as far as concerns danger from storms, may on the 

 whole be placed on about the same level as Scots Pine, which, 

 though lightly foliaged and deeper rooted, is for the most part to 

 be found on light, sandy soils. Among broad-leaved trees, Aspen, 

 Birch, and Hornbeam suffer most in exposed situations, owing to< 

 the shallowness of their root-systems, and during violent storms 

 also the Beech, whilst the deep-rooting Oak suffers least of all. 



Young crops are damaged only exceptionally by storms: the 

 danger begins with advancing age, and increases with the same, and 

 consequently with long periods of rotation. Coppice-woods rum 

 no risk whatever, copse only comparatively little, and then accord-i 

 ing to the nature of the standard species, whilst it is only in high 

 forest that extensive damage is done. Those high timber forests, 

 whose yield is not harvested in regular annual falls or clearances, 

 but by the selection of the mature stems here and there through- 

 out the whole area under wood, and in which the individual 

 trees have freer space for their development, acquire much greater 

 power of resistance than such as are grown with the stock con-j 

 sisting of regular annual or periodic falls of equally aged crops! 

 In the latter, too, the method of reproduction is also of influence j 

 for where the smaller areas that would otherwise be allotted tc 

 several annual falls are included in one periodic fall for the pur- 1 

 poses of natural regeneration, the interruption of the canopy during 

 the preparatory and reproductive fellings, as well as throughout | 

 the subsequent clearances of the parent trees, causes the crops t(! 





