THE VOICE OF THE DESERT 



46 



to draw water, and the mature specimens are those 

 which have successfully defended the plot of ground to 

 which a seedling staked a claim perhaps a century ago. In 

 a deciduous forest the contest between individuals is liter- 

 ally for a place in the sun. Where the saguaro grows there 

 is enough of that for everybody. But every individual 

 must protect his water rights in his own area. 



For all the soft succulence of the saguaro's trunk, for 

 all the fact that it is not, like a tree, predominantly woody, 

 there is nothing weak about its structure. It may sway 

 in the wind like an oak or an elm; in a storm, branching 

 "arms" may sometimes break off, or the whole may be up- 

 rooted. But the massive trunk is surprisingly strong. In- 

 deed, when you realize that the flesh beneath the waxy 

 skin is soft and pulpy, it is astonishingly so. 

 " Examine the skeleton of a dead specimen lying on the 

 desert and the mystery is explained. The soft part decayed 

 rapidly but there remained the almost indestructible 

 woody "ribs," each as long as the saguaro was high. Among 

 the many remarkable discoveries of this cactus was the 

 discovery of the principle of "reinforcement" which man 

 now takes advantage of when he embeds steel rods in his 

 concrete walls. The center of the saguaro is pulpy and 

 so is the outer flesh. But imbedded in this pulp is a cylin- 

 der of closely placed rods which give the whole a flexible 

 strength. Since the time before history, Pima and Papago 

 Indians living in the saguaro country have used these 

 rods to construct wooden shelters which must be as im- 

 mune to decay as cypress. 



In another way also, the saguaro finds that its ability to 

 produce either pulpy or extraordinarily hard tissue comes 

 in handy. It is very much subject to the attack of wood- 



