BRITISH FOREST TREES 115 



It is not indigenous to north-eastern Europe above 515 

 latitude, hut finds its natural home in the mountains of 

 eastern France, south-western Germany, Bohemia, Hungary, 

 Tyrol, and Switzerland, where it is met with on the out- 

 lying and lower hills, generally forming mixed forests 

 with spruce, beech, or larch, rather than pure forests. 

 Where it occurs to the north of 51^ latitude its intro- 

 duction has been due to artificial means. It was intro- 

 duced into Britain early in the seventeenth century (1603). 

 Trte-furm and Root-system. The silver fir resembles the 

 spruce in the formation of a straight long bole, which 

 approaches the cylindrical shape, yielding a maximum of 

 timber and good long squares. Its thickly-foliaged, though 

 narrow, but deep-reaching crown is supported by a some- 

 what sparse branch development, subdivided, however, into 

 a large number of twigs, on which the short needles are 

 retained from six to nine years, thereby giving great density 

 of leaf-canopy. The shape of the crown is less conical 

 than that of the spruce ; in older trees it generally becomes 

 somewhat bushy after the growth in height is practically 

 completed, and makes the crowns look from a distance as if 

 a large nest had been built near their tops. Its demands 

 on growing-space are therefore on the whole of a very 

 moderate character, although not quite so limited as in the 

 case of spruce. 



The silver fir is a deep-rooting tree. Its tap-root resolves 

 itself at an early age into several main branches, which push 

 their way deep into the soil and form a heart shaped root- 

 system ; side-roots developed near the surface also tend to 

 penetrate into the lower layers so long as the soil is not 

 wanting in depth. 



Requirements as to Soil and Situation. For normal 

 development the silver fir requires 1 a mean annual tempera 



1 Willkonun, Die Fontliche Flora, -<-., 1887, p. 103. 



I 2 



