86 BRITISH FOREST TREES 



leaved deciduous trees have previously allowed the soil to 

 become deteriorated and impoverished. 



Spruce thrives on soils of the most varied description, 

 from the strong, friable mountain soil down through the 

 binding varieties to the sandy-loamy, and the drained moors 

 and bogs. Soils that show any good growth of weeds like 

 Epilobium, Senccio, Atropa, or Digitalis, or of grasses like 

 Carex are generally fresh and capable of producing good 

 spruce forests, as also are those with high growth of whortle- 

 berry ; but on tracts covered with heath and heather plan- 

 tations should more frequently be made with spruce and 

 Scots pine, than with spruce alone. It is not indifferent 

 to mineral strength, but the chief factor in determining the 

 suitability or non-suitability of any particular locality is 

 certainly the equable distribution of a moderate quantity of 

 moisture throughout the soil. The older sand formations, 

 and loamy deposits resting on limy subsoil found in Alpine 

 districts bear good spruce forests, but on limy soils it is apt 

 to suffer from fungous diseases. On marls, loams, and rich 

 clayey soils, deciduous broad-leaved trees find a more suit- 

 able home than the spruce. Low sandy plains with dry 

 gravelly soil, soured undrained stretches with stagnant soil- 

 moisture, moorpan with excess of sesquioxide of iron, or 

 tracts liable to inundation are not the localities on which 

 spruce can be expected to attain its normal development. 



The most suitable aspect depends on the locality, and the 

 elevation above the sea-level. Towards the lower limit of 

 its proper region it prefers the cool, moist, north and north- 

 east exposures, whilst towards the upper limit it seeks the 

 southern and south-western aspects in order to obtain the 

 requisite degree of warmth, and to escape from the drying-up 

 influence of the east winds. 



Requirements as to Light. The ability to retain its 

 branches in foliage for five to seven years, and the conse- 



