128 THE DEVELOPMENT OF BRITISH FORESTRY 



production of timber is limited accordingly, apart alto- 

 gether from climatic conditions. 



In the west of Ireland and parts of Scotland large 

 areas of surface occur at 200 to 300 feet above sea-level, 

 counterparts of which would scarcely be found under 

 3000 or 4000 feet in Southern Europe. The relative 

 proportion of non-productive timber-land to total surface 

 in the mountain range of European countries increases 

 with the latitude, and while the effect of elevation is seen 

 for every 100 feet or so above 500 feet in Great Britain, 

 little definite effect can be noticed over the greater part 

 of the Continent until altitudes of 2000 or 3000 feet have 

 been reached. 



Soil changes due to climatic influences, of course, go on 

 in all countries. Ramann, writing of the soils of North 

 Germany, describes these changes in the following 

 words ^ : — 



' There are in Europe three plant formations constantly 

 in opposition — the peat against the forests of the north, 

 the heath against the broad-leaved forest, and the latter 

 against the steppes. The soils of North and part of 

 Middle Europe are geologically young, and a comparatively 

 short time ago other vegetative forms predominated than 

 those found to-day. These soils are glacial and steppe 

 soils left from diluvial and post-diluvial times. The 

 weathering of glacial soils is far advanced only on the 

 poor sands, and even here not universally. We find the 

 diluvial sands of the North German plain free of un- 

 combined lime for considerable depths, the original lime 

 having been washed out, but the weathering of the 

 silicates has seldom proceeded deeper than ten inches. 

 The leaching out is slow, and the predominating vegetation 

 assists the soil in checking it. The annual leaf- fall returns 

 mineral constituents to the surface which have been ab- 



1 Bodenhunde. 



