44 FOREST PLANTING. 



more the soil is liable to quickly evaporate its moisture, 

 the more evident is the beneficial result of an abundant 

 stock of water in the subsoil to the vegetation. In the 

 not drained lowlands along the rivers, the water table is 

 on the level Avith the river. But the moisture of the 

 soil, owing to the capillary attraction, rises above this 

 station so that the less is done in the way of drainage, 

 the higher penetrates the humidity in those lands. Tliis 

 holds principally true in regard to swampy grounds or 

 moorlands, which, owing to their sponge-like structure, 

 are able to receive enormous quantities of water, and to 

 retain it. 



The injurious effects of wet soils to the growth of 

 trees can easily be observed. Such soils are cold and do 

 not retain warmth ; whereas forest vegetation requires 

 more than any other plant a warm soil. Moreover, a 

 wet soil disolves the vegetable food contained therein 

 rapidly, and carries it down into the subsoil, where it is 

 inaccessible to the roots of young trees. Thus the upper 

 soil is sometimes entirely washed out, losing a great deal 

 of its power to sustain plant growth. An excess of 

 moisture in the upper soil prevents access of air, and 

 consequently there does not properly go on the decom- 

 position of organic matter, nor the disinteqratio7i of the 

 minerals contained in the ground, both chemical actions 

 being necessary for the sustenance of plant life. When 

 organic matter in the soil decomposes while in contact 

 with an excess of moisture, there n'ill be produced acetic 

 acid and other organic acids, which soon make the ground 

 sour. Then the formation of impenetrable layers of 

 protoxide of iron will commence, and that means death 

 to every vegetation. To the spongy, swampy soil, exces- 

 sive quantities of water arc especially deleterious, these 

 swelling uj) the j^ores in the ground so greatly as to dis- 

 turb the development of the tree roots, and causing, 

 during the spring, late frosts. 



