CITRUS CONDITIONS NORTH AND SOUTH 359 



DISTRIBUTION OF CITRUS CONDITIONS IN 

 CALIFORNIA 



The claim has been made above that citrus culture conditions exist 

 in suitable situations in central and northern California from Shasta 

 to San Diego county, and historical evidence has been cited to prove it. 

 It is so surprising that practically the same climate should be found 

 through a distance of between seven and eight degrees of latitude that 

 many, even of those who have lived in California, do not appreciate the 

 fact, nor know the explanation of it. An effort is made toward such 

 explanation in Chapter I of this work. Even at the risk of repetition 

 the subject will be reviewed with special reference to the occurrence of 

 conditions affecting the growth of citrus fruits. 



First: California is not only blessed with benign ocean influences, 

 but northern California is additionally protected from low winter tem- 

 peratures by the mountain barrier or the Sierra Nevada, extending 

 southward from the multiplied masses of protecting elevations in the 

 Shasta region, while Southern California enjoys the protection of the 

 Sierra Madre and other uplifts on the north and east of her citrus 

 region. Northern blizzards are, therefore, held back from entrance to 

 California and are forced to confine themselves to southerly and easterly 

 directions over the interior parts of the Pacific slope, while the great 

 blizzards of the northwest traverse the Mississippi Valley and, if they 

 have sufficient impetus, extend to the gulf and carry destruction to 

 semi-tropical growths even in northern Florida. The ocean then bring- 

 ing warmth and the high mountains defending against cold, combine 

 their influences to give nearly the whole length of California semi- 

 tropical winter temperatures. 



Second: Although this striking similarity does exist, in citrus dis- 

 tricts north and south, there is another even more startling proposi- 

 tion involved and that is the influence exerted by the presence of the 

 coast range as the western boundary of the great interior valley of the 

 State, and intervening between that great valley and the ocean. The 

 several ridges of the coast range with their enclosed small valleys serve 

 as a colossal wind-break against northwest winds, which might other- 

 wise, now and again, bring a temperature too low for citrus fruits, 

 where now they are safe from injury. The chief effect of these moun- 

 tains is to protect the northern interior valleys and foothills from the 

 raw winds of early springtime and to allow the sun as he crosses each 

 day higher in his course, to expend the increasing heat directly in pro- 

 moting vernal verdue. The result is a protected interior region in 

 central and northern California, of quick growth in all lines early 

 pasturage, early grain harvest and early fruit ripening. The valleys 

 of southern California, which have thus far been largely developed, 

 have no high range between them and the ocean. They are open on the 

 west because the coast range of mountains takes a sharp turn eastward 

 in the southern part of the State and afterward curves southward, pass- 

 ing along the eastern side of the chief productive region. The influence 

 of this opening of the valleys of southern California is not so unfavor- 

 able as such opening would be at the north, because ocean winds are 



