DAMAGE CAUSED BY ATMOSPHERIC PRECIPITATIONS. 23 



A. EAIN. 



15. Injuries caused ly Rain; Preventive Measures. 



In general, the effects of rainfall are in the main beneficial, as 

 the vegetation thereby receives the supplies of moisture so essen- 

 tially necessary for its thriving. The continuous want of rain 

 in summer, especially during May, is often productive of the 

 worst results for young sowings, and for transplants that have not 

 yet established themselves in their new abode. A rainy year is, on 

 the other hand, always advantageous for woodland growth, as the 

 young crops prosper well, and plants and trees injured by late 

 frosts or insects get a quicker and fuller flush of new foliage, so 

 that a very large rainfall can only be injurious on soils that are 

 of themselves moist. 



But rain can also be of itself injurious if falling in sheets or 

 descending with great violence as a water-spout, when large 

 quantities of water reach the ground in a short time, whilst less 

 violent rainfall is also injurious, if of long-continued duration. 

 Scouring and washing away of the soft upper soil from unprotected 

 hillsides, and of the layers of dead foliage and humus from better 

 protected areas, washing out of the seed from sowings and seed- 

 beds, interferences with the latter, more especially on slopes, and 

 damage to ditches and roads, are not infrequently the results. 



The means of preventing such damage consists chiefly in the 

 maintenance of a suitable stock or crop of timber on steep hill- 

 sides, judicious and gradual reproduction of the same, avoidance of 

 grubbing up the stools, and retention of the soil-covering of 

 undergrowth, brushwood, moss or dead foliage. The very great 

 importance of woodlands, and of their natural soil-covering on 

 steep slopes, more especially in mountainous tracts, is now 

 thoroughly recognised, in respect to the regulation of the running 

 off of moisture, the prevention of the scouring and washing away 

 of the surface-soil or of inundations, the maintenance of a 

 gradual circulation of moisture for the perennial feeding of 

 springs and brooks, in short, their influence as protective 

 forests. The woodland crops break the violence of rainy down- 

 pours ; stumps, roots, and, above all, the layer of dead foliage and 

 moss, hinder the speedy off-flow of the water that has reached the 

 ground, and give it time to percolate into the soil ; fallen leaves 



