22 STATE BOABD OF HORTICULTURE. 



Table of Citrus Fruit Products — Cotitinued. 



Especially Favorable and Dangerous Localities. — All 



along the belt of country from Tehama County to San Diego 

 there are especially protected or favored localities where the 

 orange and the lemon grow to perfection, and also locali- 

 ties where it would be unsafe to attempt citrus fruit culture 

 as a commercial enterprise. This is caused by the local 

 topography of the country and does not depend much on the 

 altitude. Wherever cold currents of air from high altitudes 

 flow to the valley without interruption it will not be safe to 

 attempt citrus culture at any elevation within the sweep of 

 these currents. On the other hand, wherever these descend- 

 ing currents are cut oft or turned aside by spurs of the moun- 

 tains, leaving the warm atmosphere of the days undisturbed 

 during the nights, there orange and lemon culture may be 

 engaged in without danger from frost. In other words, the 

 eddies of air currents must be selected and the main flow of 

 these currents must be avoided. 



Every one who has traveled along these Sierra foothills 

 parallel with the valleys, particularly in the winter season and 

 at night, will recall his surprise at the sudden changes of the 

 temperature of the atmosphere within short distances. He 

 may also remember to have noticed tender plants and shrubs 

 seared and frost bitten, while just over a ridge or cone the 

 same plants and shrubs were in full leaf and growing luxuri- 

 antly. Want of attention to these facta has caused many a 

 disastrous failure in the cultivation of citrus fruits in 

 California. 



