26 DROUGHT RESISTANCE OF OLIVE IN SOUTHWESTERN STATES. 



tion is dead, but those alive are small and in bad condition. Figure 

 6 shows very distinctly the effect of the cottonwood growth on the 

 olives. The struggle has been so intense for a bare survival on the 

 part of the whole plantation that the competition with a powerful 

 feeder like the cottonwood has proved fatal, though the cottonwoods 

 probably, survived the olives but a few years. 



Crossing the conduit to the next 20-acre block, only half of which 

 was set, are two small blocks of olives, 6 acres in all, with 4 acres of 

 figs between them. Here the contrast between the green of the olives 

 on either side and the figs, which are dead save a few struggling 

 sprouts, illustrates in a most marked way the comparative drought 

 resistance of the two. Indeed, of exotic trees on this ranch only the 



Fig. 6.— Olive trees which have died through competition with a row of cottonwood trees on the Pope 

 olive plantation, near Palm Springs, Cal. (From a photograph.) 



pepper trees bordering one field show an ability to endure these 

 extreme conditions equal to that of the olive.'* 



While trees of this slow growth and evergreen nature are conse- 

 quently slow in forming what the foresters call dominant and sup- 

 pressed classes, a close inspection of this grove shows such a work to 

 be in progress, not as is generally the case in a forest by the process 

 of dominant trees overtopping and shading the weaker ones, but by 

 means of dominating root systems by which once a tree has gained 



n A visit was made to this plantation on April 13, 1908, at which time about 20 per 

 cent of the trees of the more resistant variety of olives was in blossom, but at a later 

 visit, June 11, not a single fruit could be found to have set. On the same date two 

 olive trees in Dr. Wcllwood Murray's irrigated garden in Palm Springs village were 

 carrj'ing fair crops of fruit. 

 192 



