PROTECTION FROM FROSTS 



Seed Much that has been said > Chapter 

 will be suggestive to one who desires to grow his own shelter 

 trees from seed. Trees from small seeds are best grown in boxes 

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

 best when put in permanent place when quite small. Whether put 

 at once m permanent place, or in nursery, the land should be deeply 

 worked and the young plant well planted and cared for. 



Cultivation of Shelter Tr,ees. 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 al- 

 lowing 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 en- 

 rich 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 Cali- 

 fornia. 



PROTECTION FROM FROSTS 



Much attention has been given during recent years to the pro- 

 tection 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 ex- 

 posure 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 result has been secured by checking 

 radiation of heat by covering the orchard or vineyard with a cloud 

 of smoke. Both these protective measures fail when the tempera- 

 ture 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 

 manufacturers. 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 Ex- 

 periment Station, but conclusions are not available at this date. 

 They must be looked for in Experiment Station bulletins, in the pub- 

 lications of the U. S. Weather Bureau* and in 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 thorough- 

 ly and economically done, it is a most profitable investment and 

 should be studied by all growers. 



*The latest review of the subject is to be found in Farmers' Bulletin, No 1096. on 

 "Frost and the Prevention of Damages by It." It can be had free by writing to the 

 U. S. Department of Agriculture, Washington, D. C. 



