liKITISII FOREST TREES 31 



The power of accommodating themselves to situations not 

 naturally suited to their growth and normal requirements is 

 greatest in the Scots pine and birch, less pronounced in 

 the oak, beech, spruce, silver fir, Austrian and Weymouth 

 pines, and least of all in the ash, elm, maple and sycamore. 



It is impossible to say that clayey, loamy, limy or sandy 

 soils are necessary for any particular species of forest tree ; 

 extracts from the works of the most eminent German 

 sylviculturists are often absolutely contradictory on such 

 points. G. Heyer 1 on the other hand even went so far to the 

 other extreme as to assert that almost any soil could produce 

 any kind of timber, provided it were supplied with the 

 necessary and suitable quantity of moisture. Ney 2 ably 

 summarises as follows : 



"As regards chemical composition of the soil, even slightly sour 

 marshy soils are unfavourable to all species of trees except alder, birch, 

 and spruce, whilst sour soils liable to dry up at certain seasons are 

 unsuited for all except birch, spruce, Scots and Weymouth pines. 

 Only these last-named species thrive on pure peat, and not even the 

 spruce when it is dry. Ash, maple, sycamore and elm require a 

 moderate quantity of lime in the soil, and beech, hornbeam, oak, as 

 also larch and Austrian pine, thrive best on soils that have at least 

 some lime in their composition. The hardwoods oak, ash, maple, 

 sycamore, elm, chestnut, beech, and hornbeam also appear to demand 

 the presence of a considerable quantity of potash, whilst on the other 

 hand spruce, silver fir, and especially Scots pine and birch, thrive on 

 soils rich neither in lime nor potash." 



It seems hardly open to question that the one factor in 

 regard to the soil of greatest importance from the sylvi- 

 cultural point of view is humus; 31 given a sufficiency of 

 vegetable mould or humus, all the physical factors are affected, 

 and soils otherwise unsuited for the growth of the more 

 exacting species become perfectly well adaptable to their 



1 G. Heyer, Forstliche Bodcnkuntie und A'litnatologic, 1856, p. 488. 



2 C. E. Ney, Die Lehrevom Waldban, 1885, p. 64. 



3 By humus or leaf-mould is meant all organic matter ttndergoing the 

 process of decomposition (Liebig). 



