322 BRITISH FOREST TREES 



also to a very considerable degree the denizens of the lower- 

 lying and moister lands. 



Although naturally classifiable as belonging to the less ex- 

 acting species of forest growth in regard to fertility of soil, 

 a due measure of mineral strength and a rich admixture of 

 humus are requisite before highly remunerative returns can 

 be expected from withy-beds and osier cultivation. This may 

 be seen in the beneficial effect of silt-deposits during inun- 

 dations, and of manuring, ploughing, or trenching, as on 

 agricultural tracts, in upland plantations, where a good quality 

 of soil and subsoil appears to satisfy the general requirements 

 for a greater amount of moisture, bringing nutriment in 

 solution, at lower elevations. 



It has always been the custom to regard the willow- 

 tribe as naturally and principally confined to the moister, 

 lower lands ; but the financial success of the osier-farm on a 

 well-drained upland site at Freising near Munich proves that 

 on good soil less moisture is requisite, as of course is quite 

 in accordance with the laws of nature regulating tree- 

 growth. 



Although not developing a deep root system, depth of soil 

 is one of the requisites for successful willow cultivation, 

 whilst porosity and penetrability, affording easy passage to 

 the atmosphere as well as to the rootlets, are factors that 

 also make their influence beneficially felt in increased pro- 

 duction. Where the soil-moisture is brackish or salt, 

 willow cultivation is less satisfactory. Willow-culture is also 

 often of great benefit in reclaiming land ; the stools and 

 shoots collect the silt brought down during inundations, and 

 assist greatly in gradually raising the soil above the flood- 

 level (see page 228). 



Requirements as to Light. Capacity for thriving under 

 side shade or overhead shadow is perhaps even less attribut- 

 able to the willows than the poplars. Both tree-willows and 



