114 THE DEVELOPMENT OF BRITISH FORESTRY 



are given by Endres as 4000 feet for beech, and 1000 feet 

 for oak, ash, and elm. In the Riesen-Gebirge spruce 

 reaches 5000 feet, and similar examples of timber crops 

 at high elevations may be found elsewhere. In a general 

 way, it would appear that the absolute tree limit is from 

 1000 to 1500 feet higher than the timber limit. 



Whether the climate of Britain would allow better 

 results to be obtained with improved conditions of soil 

 and situation cannot be said with certainty. No doubt, 

 higher mountain ranges would provide better soils and 

 more sheltered aspects than are now found to a limited 

 extent between 1000 and 2000 feet in the north of 

 England, Wales, Scotland, and Ireland. It is conceivable, 

 for instance, that the Highlands of Scotland would give a 

 much higher proportion of plantable land if they lay within 

 the same latitudes as the south of England, but these are 

 suppositions which cannot be put to the test, and taking 

 things as they are it is no exaggeration to state that the 

 line of profitable planting on British hill ranges lies from 

 500 to 1000 feet lower than is the case in Belgium and 

 Hanover, and from 1000 to 8000 feet or more lower as 

 one goes farther south in British latitudes. How much 

 of this is due to elevation, how much to soil, and how 

 much to prevailing wind, it is difficult to say. 



Any records of temperature and wind at high altitudes 

 in Britain are too few to show clearly the climate of hill 

 ranges, but those which exist indicate that the tempera- 

 tures above 1000 to 1200 feet are below the minimum for 

 commercial timber production, except in the south of 

 England and Ireland, as shown in the table on page 94. 



In connection with the subject of climate, the acclima- 

 tisation and adaptation to environment of forest trees 

 come largely into play. All species have certain limits 

 of temperature, above or below which they do not 

 grow, or cannot survive the first winter. Somewhere about 

 midway between these upper and lower limits may be 



