216 FOREST PLANTING. 



grow up, and develop such powerful vegetation in root 

 and trunk that they, in the course of time, tear the walls 

 asunder. The wild roses, besides, have the advantage 

 of sending up many shoots, all around the stem. If 

 these shoots are laid down in from four to five inches 

 deep grooves, and so covered with earth that only the 

 tips are looking above the ground, there will be soon 

 formed such a thick net of rootlets under the surface 

 soil as to bind entirely the soil and keep it together. 



Besides the ailanthus French authorities recommend 

 for reforesting localities with rocky surfaces the larch 

 and the pine of Aleppo. The latter thrives upon even 

 the poorest soil, because it draws, like most of the coni- 

 fers, a large part of its food from the air, increases by 

 its plenty leaves (needles) the soil underneath, and is 

 not affected either by the scorching heat of the sun or 

 the blasting winter winds. 



These trees and shrubs permit even grasses to grow 

 under their shade, and thus aid to increase the mold on 

 the rocky surface by the successive growth and decay of 

 the vegetation, enabling us, as time goes on, to plant 

 more valuable trees. 



It happens very often that the soil upon the said 

 terraces is neither sufficiently thick nor stable 

 enough to furnish a good bed to the young trees. 

 They grow there very slowly and poorly, their roots 

 being unable to hold on the little soil which should 

 cover them, but is washed away by rain, so that the 

 roots receive their subsistence only by the humidity 

 retained on the overlaying stones. In such cases we 

 have to sow quickly and vigorously growing fodder 

 grasses, either before planting or shortly afterwards, as 

 these at first give the best protection for young trees 

 against meteorological influences ; and later, when de- 

 cayed by the shade of the growing trees, they increase 



