548 



SCIENCE. 



[N. S. Vol. III. No. 67. 



where there is no earth in sight at all 

 clinging to the sides of cliffs, so bare that 

 the roots run along on the surface entirely 

 uncovered until they reach some crevice 

 which thejr fill, and send tendrils down to 

 draw sustenance from an unseen source. 

 In such places the melting snow disappears 

 quickly from the surface, and, except for 

 their influence in keeping the soil light 

 and porous so that the water can be ab- 

 sorbed readily instead of running off, it 

 matters but little whether trees are there 

 or not. N"o moisture remains on top of 

 the ground long for shade to protect. It 

 goes either into the air or else into the 

 ground, and it is a well known fact that a 

 very large portion of the water which flnds 

 its way down the steep sides of the Sierras 

 disappears near its sources and is found 

 again far below, either in springs, by 

 means of artesian wells, or in the increased 

 flow of the parent stream. Indeed, a num- 

 ber of very respectable rivers, not only in 

 the mountains, but in some of the valleys, 

 seem to owe their existence to such distant 

 and hidden sources. If the trees have any 

 direct power here it seems to be to draw 

 from deep beneath the surface the moisture 

 which has sunk into the earth and exhale 

 gallons and gallons of it hourly. Any 

 good sized tree has been estimated to have 

 a capacity of forty or fifty gallon every 

 twenty-four hours, and a forest of such 

 trees would effect very considerable re- 

 sults. I should like to offer the opinion of 

 Captain J. B. Overton, of Virginia City, 

 Nevada, just here. He has had control of 

 the water supply of that city for many 

 years, and also conducted large operations 

 in the mountains in cutting timber, wood 

 and lumber, for the mines. His experience 

 covers a quarter of a centurj' and extends 

 over several townships of land, from which 

 his men cut the timber. He says "My ex- 

 perience proves to me that the cutting of 

 the timber makes no difference in the 



amount of snow that falls, but that it drifts 

 more, and for that reason lasts about as 

 late in the summer as it would before the 

 removal of the shade. I do not think the 

 streams get low any sooner or afford any 

 less water. I am of the opinion that the 

 trees absorb from the soil quite as much 

 water as would be evaporated by the action 

 of the sun in the absence of shade. I 

 know two small springs that ran for the 

 whole year for ten years after the laud was 

 cut over, but, that since the thrifty growth 

 of young pines have reached a height of 

 from 15 to 25 feet and shade the ground 

 as well, if not better, than the large trees 

 did, have dried up about the last of August 

 for five years past, and I can see no cause 

 for it except that the trees are using the 

 water. The supply of water used by ray 

 company in its operations has not decreased 

 with the disappearance of the timber, and 

 I do not find that the freshets are anj^ more 

 frequent or more violent than before the 

 trees were cut off. The trees are coming 

 up in a second growth much more numer- 

 ously than they were before, and after 

 sixty or seventy years about nine-tenths of 

 them will die off and decay, leaving the 

 timber about as it was when we first came 

 to the country ; then I think my springs 

 will flow again. My observation teaches 

 me that the amount of rainfall is not 

 affected by denuding the mountain -side, 

 but that the surface of the ground will be 

 heated more by the sun and will therefore 

 be drier, but that the springs and streams 

 will be more diminished by the water used 

 by the trees than by evaporation in their 

 absence." 



In a timber belt the snowfall is compara- 

 tively evenly distributed and by the radia- 

 tion and reflection of heat from its own 

 body each particular tree immediately sets 

 itself to work to clear the ground around it, 

 and long before there is a vacant foot out 

 in the open a space will be bared for several 



