202 FOREST PLANTING. 



which we have extensively ventilated on page 148 

 (Part II.) alongside the banks is the cheapest and 

 safest means. The natural location of the willow is in 

 low bottom-lands which are exposed to occasional inun- 

 dations. If planted upon the banks of a river, the wil- 

 lows will thrive and retain, in case of the overflowing 

 river, a great mass of earthy substances enmeshed in its 

 net-work of fibrous roots, after the waters have sub- 

 sided. At the same time the spongy banklands are 

 made more compact by the luxurious growth of the 

 willow-roots, and able to better resist encroachments 

 caused by the current of the waters. 



In the same proportion in which thus the running 

 waters, by the gradual elevation of the banks and their 

 greater consistency are rendered more narrow, the depth 

 of the slanting bed will increase, owing as every 

 engineer must admit to the increased force of the nar- 

 rowed river current. This change produces two very 

 desirable conditions. Firstly, the lands situated behind 

 the willow plantation are protected against inundations 

 by the elevated banks and, secondly, the flow of the 

 deepened and, therefore, largely augmented river is, 

 owing to the decreased slant in the bed, running slow- 

 lier, thus contributing much more water, during a lonyer 

 period of the year to the receiving river below than the 

 former shallow overflowing rivulet. 



If the banks of the rivers in the mountain valleys 

 consist as is often the case of gravel, sand and stones 

 carried down by the torrents from the high mountains, 

 the willow cannot be grown on such soil successfully. 

 In that case we select trees and shrubs which are in this 

 respect less exacting in regard to location, as, for instance, 

 the poplar, birch and alder. These will grow, if planted 

 respectively as cuttings or as seedlings, on such soil. If 

 the plantation be well looked after, there will soon, by 



