200 THE DEVELOPMENT OF BRITISH FORESTRY 



The majority of broad-leaved trees, such as oak, ash, sj'ca- 

 raore, elm, chestnut, etc., are all lovers of good soil, and 

 with the exception of the last named, require a fair 

 amount of moisture to produce heavy timber. Beech is 

 perhaps the only important tree which will reach a fair 

 size on thin, dry soil, but even with this species fertility 

 is not a negligible quality. With conifers, on the other 

 hand, quality of soil is not such an all-important point. 

 Scots pine, Douglas fir, and silver fir require a certain 

 depth, but not necessarily great fertility, while spruce 

 and larch will grow on the thinnest soil provided 

 that sufficient moisture is available during the growing 

 season. This capacity of the conifers for growing on 

 poor soils has doubtless been exaggerated by many 

 foresters, until it has almost become a proverb that 

 they will succeed without soil at all. They will, at 

 any rate, produce heavy crops of timber on land too 

 poor to give a profitable crop of oak, ash, or even 

 beech, and their value as timber species is increased 

 accordingly. 



Assuming that the poverty of soil increases with a 

 decrease in the depth of porous and aerated material, 

 whether loam, sand, clay, or gravel, it would follow that 

 shallow rooters such as larch or spruce are of more im- 

 portance in forest economy than deep-rooting species. 

 While the former will grow on deep soil, the latter 

 will fail to produce a profitable crop on shallow ground. 

 Given certain physical and climatic conditions, therefore, 

 spruce and larch may be considered capable of growing 

 on soil absolutely worthless for any purpose of an agri- 

 cultural nature. These different species of trees, there- 

 fore, must take first place in British forest economy 

 in mountain districts. 



Next in importance comes species demanding a certain 

 depth, but content with comparatively poor and dry 



