STORMS. 535 



When species such as silver-fir, or Scots pine, with strong 

 root-systems, are hindered from developing them normally, 

 owing to the nature of the suhsoil, they are exposed to danger 

 equally with the spruce, and even more so ; for in such cases 

 they are compelled to have shallow root-systems which, unlike 

 the spruce, they rarely develop evenly in all directions. 

 Danger is also increased in the case of the Scots pine by the 

 higher centre of gravity it possesses than the spruce. 



A list of species arranged in ascending order of storm- 

 firmness can therefore be drawn up only after allowing for 

 the effects of local circumstances on each species, and pre- 

 supposing a rational treatment in accordance with sylvicultural 

 requirements. 



From this point of view, conifers are arranged in the follow- 

 ing order : — Spruce, silver-fir, pines and larch. Of the pines, 

 the mountain and Cembran pines are most storm-firm, then 

 the Corsican pine, the Black pine, and the cluster, Weymouth 

 and Scots pines. 



As regards broad leaved species, those which are shallow- 

 rooted, such as aspen, birch, beech, and hornbeam, are least 

 storm-firm. The beech is more frequently blown down than 

 any of these species, because it is most abundantly grow-n. In 

 the woods above G^rardmer, in the Vosges, the porportion of 

 beech increases under natural regeneration with the altitude, 

 in the mixed forest of silver-fir, spruce, and beech ; and at the 

 crest of the mountains, 4,000 feet, beech alone remains, the 

 conifers being unable to resist the prevailing westerly gales. 

 Tlie following trees are fairly stoim-firm : — ash, sycamore, 

 Norway maple, elm, alder, lime and walnut; the deep-rooted 

 oaks withstand storms best of all. 



(h) A(/c of Tree. — Storms chiefly damage woods of advanced 

 age, the second half or last third of a rotation being most 

 endangered. , 



Extensive damage is rare in woods under sixty years of 

 age, and occurs only upder exceptional conditions, sucii as 

 shallow-rootedness of young woods, soil without mucli con- 

 sistency owing to saturation by rain, woods in very exposed 

 localities or when assailed by exceptionally violent storms. 



Damage to young trees consists more in causing them to 



