252 



INDEX. 



Keforestation of mountains, French 

 code for, 159, 160, 161, 162, 

 163. 

 various methods employed in, 



156. 



when possible, 155, 156. 

 Regions, steppe, peculiar distribu- 

 tion of moisture causing, 43. 

 Reservoirs, definition of, 109. 

 River basin, definition of, 111. 

 rafts, 67. 



system, definition of, 111. 

 Rivers, cause of difference in size 



of, 110. 

 Roads, demands of, for removal of 



forests, 11. 



Rocks, agencies causing disintegra- 

 tion of, 52, 53. 

 crystalline, original source of 



soil of, 50. 

 disintegration of, 50. 



influence of solvent 

 power of water on, 

 54, 55. 



influence of sprouting 

 vegetation on, 53. 

 influence of layer of decaying 

 leaves on disintegration of, 

 57. 



Rodents, influence of, on destruc- 

 tion of forests, 73. 



Sahara desert, appearance of plants 



on irrigation of, 34. 

 wadys in, 34. 

 Sand-bars, damages produced by, 



84. 

 Sandy soils, definition of, 50, 51. 



Scrub oak, appearance of, on burn- 

 ing over of pine forests, 36, 

 37. 

 Seeding of trees, when advisable, 



157. 

 Seeds, circumstances preventing 



germination of, 40, 41. 

 vitality of, circumstances in- 

 fluencing, 39 to 41. 

 Snow, protection afforded ground 



by, against frosts, 129. 

 Soil, alternate freezing and thaw- 

 ing, influence of, in forma- 

 tion of, 54, 55. 

 formation of, 50, 51. 

 influence of earthworm in for- 

 mation of, 56. 



influence of erosion in forma- 

 tion of, 54. 



influence of glaciers in forma- 

 tion of, 54, 59. 

 loss of, following destruction of 



forests, 81, 83, 84. 

 necessary gradual formation of, 



56, 57. 

 or cradle, necessity of, for plant 



growth, 24. 



vegetable, definition of, 60. 

 Soils, calcareous, definition of, 51. 

 classification of, 50. 

 clayey, definition of, 50, 51. 

 distribution of, 51, 52, 53. 

 gravelly, definition of, 50. 

 hygroscopic properties of, 56. 

 influence of color of, on power 



of heat absorption, 56. 

 peaty, definition of, 51. 

 power possessed by, of absorb- 

 ing gases, 56. . 

 sandy, definition of, 50. 



