CHAPTER XVII. 1C9 



PHYSICAL VIGOR— HOW MAINTAINED. 



Let us take up salient points of management that are germane to 

 this issue. 



AIR. Avoid camp grounds that are relatively low or damp. The 

 low lands in mountain valleys or cienegas are bad. The night air in 

 such situations is always colder and damper that on mesas, ledges, or 

 somewhat raised ground. Another reason for avoiding low camp 

 grounds is the danger from sudden torrential floods. These floods are 

 rare in our mountains, but they do occur. Such floods are mainly 

 confined to the eastern part of the forest reserves that from time to 

 time are covered by the Arizona summer rain belt. I have been a 

 witness in both the San Bernardino and San Jacinto ranges of sudden 

 and considerable local summer floods. The more denuded the water- 

 shed, the more violent and destructive these so-called cloud-bursts 

 become. In the desert, where the low mountains are quite bare, these 

 semi-occasional cloud-bursts will deliver for a few hours a tremendous 

 vilume' of water. The experience of the railroads crossing the desert 

 is a warning of how serious the rain delivery from a diluvial rainfall 

 on a bare watershed is. In no part of the United States has the damage 

 from washouts on railroads been so great as in the arid deserts to the 

 east of us. Miles of track have been washed out even in the Colorado 

 desert, dry and desolate as it is. And this, too, from short, local rains 

 on the low, bare mountains. Oregon, with its sixty to one hundred 

 inches of rainfall at the pass near Roseburg, shows us no such wash- 

 outs as does Arizona, with its almost entire absence of rainfall on the 

 deserts. In the one case forests detain and reservoir the great amount 

 of water, so that danger is slight, and in the other the bare rocks shed 

 the occasional water like a roof, which water destroys everything in 

 its line of escape. Everything is afloat while it rains in Arizona, while 

 everything is dry as soon as the rain is over. 



Avoid low places and especially washes or dry torrent beds for 

 camps. Take this precaution in an arid district more than elsewhere. 



The result of a large rainfall in Oregon, with forests, and of a very 

 small rainfall in Arizona, without forests, is a sermon on forestry that 

 cannot be made more forcible. In Arizona, the high mountain districts, 

 where forests still exist, show the same conservative effects on rainfall 

 delivery as do our own and the Oregon forests. 



WATER. The forest maps should show all points where water 



Cienega, low moist ground. 



