1902. 



FORESTRY AND IRRIGATION. 



249 



ing now for room to stand upon and 

 crowding close together for greater 

 strength, shall, after long waiting and 

 at last fire-killed, unlock its store of life 

 germs and scatter them with sailing 

 wings on the wind to reforest the moun- 

 tains. 



No tree shows more greenness or sym- 

 metry of growth than the Finns tnber- 

 cnlata when not crowded. Its desire 

 seems to be to cover the ground, if not 

 in numbers, then with wide-spreading 

 branches. Trees are to be found 150 

 feet high, with a bod}- two to three feet 

 in diameter. I have never found one of 

 them dying from old age. They thrive 

 where other trees would not attempt to 

 grow on the steep, hot, rocky slopes. 

 Their roots penetrate ever}- little crev- 

 ice to an incredible depth, opening 

 channels for the conservation of water 

 and mulching the surface with their 

 foliage. 



The inclosure of the cones in the body 

 of the tree precludes their use for tim- 

 ber, as the cones are too hard to be 

 sawed, thus increasing their insurance 

 of life, for if they were good for lumber 

 when they are grown some one with a 



gold bug in his eye would devise some 

 way to remove them. Their usefulness 

 consists entirely in their value as water- 

 conserv^ers and to prevent erosion. The 

 more humid regions of northern Cali- 

 fornia, Oregon, and Washington, so rich 

 in forests, will, if rationally harvested, 

 perpetually supply the coast with lum- 

 ber. Even the higher portions of our 

 southern mountains produce much good 

 timber, and if harvested by trained for- 

 esters in a rational manner could be 

 made to yield a profit and perpetuate 

 the forest ; but the slaughter practiced 

 now of the forests on the San Bernardino 

 and San Jacinto reserves is sure to result 

 in serious loss, not only in the immedi- 

 ate depletion of the water supply, but 

 by reason of the lopings (which consist 

 of at least one-half of the tree bulk) 

 being left to dry and be burned, the soil 

 that has been hundreds of years accu- 

 mulating is destroyed. The rains carry 

 the silt down onto the valley lands and 

 the summer streams vanish . This prov- 

 ident pine tree, if helped a little by man, 

 will in time cover all our mountain 

 slopes, and store our rainfall, and defy 

 the fiery element. 



ALKALI FROM IRRIGATION. 

 By Professor R. H. Forbes, 



Director Arizona Agricultural Experiment Station. 



THE University of Arizona has car- 

 ried on some interesting experi- 

 ments in connection with the rise of 

 alkali in the soil of the Salt River Valley. 

 Some of the orchards were found to be 

 in an unsatisfactory condition through 

 the increase of alkali, resulting from the 

 methods of irrigation practiced there. 

 The soil before cultivation has been ob- 

 serv'ed to contain from .02 to .09 per 

 cent of salts, evenly distributed through 

 the soil as deeply as 10 feet. 



Irrigation, however, both by the ad- 

 dition of salts contained in the water 

 and usually by the concentration of 

 salts originally in the soil, has greatly 

 changed the amount and distribution of 

 alkali. Salt River becomes strongly 



charged with soluble .salts, especially in 

 hot weather at a time of low water, 

 through evaporation and the presence 

 of seepage from irrigated districts 

 above. 



These summer w^aters are also scant 

 in quantit}' and, especially in the or- 

 chard practice of southern Arizona, are 

 rushed hurriedl}^ through shallow fur- 

 rows over the area to be irrigated, wet- 

 ting only the surface layers of soil. 

 Under such conditions uncultivated tree 

 rows and ridges and insufficientl}' cul- 

 tivated surfaces in general lose by evap- 

 oration a large part of the water applied 

 in irrigating. The alkali follows the 

 soil w^ater in its movements either up or 

 down. As the soil water, through capil- 



