CHAPTER IV 



THE HEATH FORMATION 



The great heath formation of north-west Europe is 

 typically developed on relatively poor sandy 



Distribution -, n -i r t j. • j-j. 



of the heath ^ gravelly soils whose climate is wetter 



formation. than that which gives rise to steppe. The 



steppe climate is too dry for tree growth, 

 apart from local edaphic conditions, but the heath forma- 

 tion exists side by side with woods and in many cases has 

 arisen as the result of the degeneration of woodland. 



Heath is developed in north-west Germany, Jutland 

 and the Baltic islands, Belgium and Holland, northern 

 and western France and southern and eastern England 

 and Scotland. Most of the German, Belgian and 

 southern and eastern English heaths occur in regions 

 with an annual rainfall between 25 inches and 40 inches 

 (c. 60 to 100 cm.), but the Cornish heaths and those of 

 the eastern Highlands of Scotland often receive a rain- 

 fall of between 40 and 60 inches (c. 100 to 150 cm.) in 

 the year. We do not accurately know what is the 

 upper limit of rainfall consistent with the formation of 

 heathland ; above the minimum (c. 25 inches) the heath 

 formation is mainly determined by the nature of the soil, 

 though the scarcity of heaths on the western side of 

 Scotland, northern England, Wales and Ireland where 

 there are considerable tracts of country with an annual 



