} 4 BRITISH FOREST TREES 



shape of crown ; Scots pine, elm, beech, maple, sycamore, 

 birch, sessile oak, ash, and alder assume a crown of oval 

 shape ; English oak, lime, chestnut, and hornbeam tend 

 rather to the formation of a broad, obovate crown. 



When the total growth in height is completed, with 

 advancing age all trees, with the exception of the spruce 

 and larch, assume a more or less rounded-off appearance 

 varying in degree with the natural tendency towards side- 

 branch development. 



The obvious conclusion from these facts is that forests of 

 shade-bearing species, content with limited growing space, 

 i.e. beech, hornbeam, and more particularly spruce and 

 silver fir, are able to maintain close canopy more com- 

 pletely, and for a much longer time, than forests formed of 

 Scots pine, larch, ash, maple and sycamore. When 

 further, as in the case of the oak, birch, and chestnut, 

 a decided tendency to branching growth is combined 

 simultaneously with strong demand for light, interruption 

 of the leaf-canopy takes place early and to an injurious 

 degree, and all the more when the situation generally, and 

 in particular the amount of soil-moisture, varies from that 

 best suited to the particular species. 



The Quality of the Soil exerts its special influence on the 

 growth of trees. Fresh, fertile loams stimulate to development 

 of crown, and yield fine boles though somewhat at the 

 expense of their length. Deep, fresh, light sandy soils 

 induce length of stem, with thinner crown, sparser branch 

 development, and consequently a less girth of bole. Shallow 

 and rocky soils produce short-stemmed trees, with strong 

 tendency to branching and crooked growth. 



Situation. With increasing elevation the forest trees have 

 a diminished tendency towards stem-development, and an 

 increasing tendency towards branching growth, until finally, 

 towards their limit of growth, they resemble shrubs rather 



