206 AMERICAN POMOLOGY. 



moderate, not to cut off, the aerial currents ; in this all 

 will agree, and those who have any sympathy for a tree 

 will surely prefer to have the blasts, that sweep over miles 

 of open country, somewhat checked and tempered before 

 reaching either themselves or their orchards. The testi- 

 mony as to the effects of cold in sheltered and in exposed 

 situations, it must be confessed, appears somewhat contra- 

 dictory; but this is because we have not all the elements 

 of a complex problem. 



WINTER-KILLING. A most serious evil, both to the nur- 

 seryman and orchardist, is the severe injury sometimes 

 done to the trees by frost. This is commonly known by 

 the term " winter-killing," which has, at times, destroyed 

 millions of trees, and thus blighted the hopes of long-con- 

 tinued labor and large investments of capital. Some or- 

 chardists have been disheartened, and have given up in 

 despair. The investigation of the causes of this disaster, 

 and the conditions under which it occurs, will be of great 

 value to future planters ; and though, perhaps, we have 

 not yet at command sufficient data for the full explanation 

 of the phenomenon, it may be well to look into the attend- 

 ant circumstances that have; been observed ; and as some 

 of the most important considerations depend upon the soil 

 and exposure, they may be well introduced in this place. 



'I have already alluded to the theory, that the north hill- 

 sides maintain a later growth than other situations, and 

 have slated that the facts do not sustain the position. 

 The warm exposures on southern slopes and sheltered 

 nooks, are apt to favor the premature starting of the sap 

 in the mild weather that often occurs during the winter, 

 in our changeable climate. On the prairies, and on flat 



