74 POPULAR FRUIT GROWING. 



"A general idea of the operation of frost fighting may be 

 gained from a brief description of the work observed in a grove 

 on a cold night. There were twenty-five perforated sheet-iron 

 stov-es scattered over each acre of grove, one stove being placed 

 in the center of the square between four trees. These stoves 

 were filled with a prepared mixture of shavings, asphaltum, and 

 crude oil. When it was determined to light the fires a force of 

 men appeared, each one carrying a can of oil and a torch. A 

 small quantity of oil was pour-ed over the smudging material 

 and was then quickly lighted with the torch. As soon as all 

 the fires were burning, the men returned home, except one man 

 to about 5 acres, who kept the fires replenished and in good, 

 burning condition. 



"Just how much benefit is derived from these various devices 

 it is difficult to estimate, as the experience of the growers is 

 conflicting and the experiments that have been conducted have 

 not always been comprehensive. There seems to be no doubt, 

 however, that the judicious use of the various devices used in 

 frost protection has been of great commercial value. One who 

 has had an experience of many years and who has large finan- 

 cial interests involved writes: 



" 'We have been able to protect against the severest cold 

 we have had since we secured the coal baskets. Several times 

 the temperature has been around 24* or 25 until we got our coal 

 baskets under way, but we were usually able to make a change of 

 from 3 to 5 when our baskets were lighted and were giving off 

 a good heat.' 



"Aside from the injury to the fruit and the young wood by 

 frost, continued cold weather causes the wood of the lemon 

 trees to mature and the fruit to develop a coarse, rough texture 

 and to ripen prematurely." 



QUESTIONS CHAPTER V. 



1. What is sunscald and how can it be prevented? 



2. What injuries to trees are caused by birds? By cattle? By 

 wind? By mice and rabbits? By cultivation? 



3. WTiat are root galls? 



4. What effect does winter injury have upon orchard trees? 



5. How may twigs, trunks, roots and buds be protected from 

 winter injury? 



6. Into what classes may plants be divided, considering their 

 susceptibility to frosts? 



7. When are injurious frosts most likely to occur? 



8. By what means can frosts be foretold? Explain each. 

 J>. In what ways may trees be protected from frosts t 



