NATURE AND FORMATION OF SOILS. 



29 



ical removal of the soil (Fig. lo) by heavy rains 

 or wind. Dense forests serve as windbreaks, and 

 soil blown by the wind is lodged and prevented 

 from further transportation by the trees. These 



FIG. 9. — ROOTS OF FOREST TREES OPENING A ROCKY SUBSOIL. 



forests, with their masses of roots and decayed 

 leaves, also serve as a blanket in protecting from 

 extremes of heat and cold. 



Masses of seaweed act as barriers to the surf, 

 and the aerial roots of mangrove trees along 



