500 CALIFORNIA FRUITS: HOW TO GROW THEM 



in many cases, as with eucalyptus and cypress especially, do best when 

 put in permanent place when quite small. Whether put at once in 

 permanent place, or in nursery, the land should be deeply worked and 

 the young plant well planted and cared for. 



Cultivation of Shelter Trees. If one desires rapid growth of 

 shelter trees, they should be cultivated the first few years as thoroughly 

 as an orchard. Much disappointment results from allowing roadside 

 trees to shift for themselves in a hard, dry soil. With such treatment 

 the root extension is naturally most rapid into cultivated orchard 

 ground, which is undesirable. Cultivate and enrich the roadside, and 

 the tree will grow chiefly on the waste land. At the same time the 

 roadside will be prevented from producing vast quantities of weed seed, 

 to be blown over the fence, and the place will have a name for neatness, 

 which is too rare even in California. 



PROTECTION FROM FROSTS 



Much attention has been given during recent years to the protection 

 of citrus fruits as they approach maturity, and of deciduous fruits as 

 they are starting on their growth, from occasional fall of the mercury 

 a few degrees below the freezing point. It has been shown by ample 

 experience that fruits may escape injury by a temperature of 28 degrees 

 if the ground surface is wet and the exposure be but of short duration. 

 Fruit has, therefore, been saved by irrigation, while that over dry 

 ground has been nipped by the same temperature. About the same re- 

 sult has been secured by checking radiation of heat by covering the or- 

 chard or vineyard with a cloud of smoke. Both these protective meas- 

 ures fail when the temperature falls a few degrees below 28 degrees or 

 when such freezing temperature is continued for several hours. 



During recent years much progress has been made in preventing 

 frost by numerous small fires distributed among the trees to be pro- 

 tected and many devices to secure such distributed heat easily and 

 economically are being enterprisingly promoted by inventors and manu- 

 facturers. The extreme low temperatures of January, 1913, gave full 

 opportunities for testing orchard heating appliances and very striking 

 success was had with them. Comparative tests and observations have 

 been made by the experts of the University Experiment Station, but 

 conclusions are not available at this date. They must be looked for in 

 Experiment Station bulletins, in the publications of the U. S. Weather 

 Bureau and in the horticultural journals. The subject is clearly seen 

 to be too complex to admit of a brief generalization except to say that, 

 when orchard heating is thoroughly and economically done, it is a most 

 profitable investment and should be studied by all growers. 



SUSCEPTIBILITY OF DECIDUOUS FRUITS 



No systematic observations of danger points in deciduous fruits 

 have been made in this State, but work elsewhere is suggestive. Pro- 

 fessor W. L. Howard, of the Missouri Experiment Station, after arti- 



