26 ORCHARD FRUITS IN VIRGINIA AND OTHER STATES. 



far as they can be represented in tabular form, may be had. The 

 usual extremes of temperature are made apparent, and some idea of 

 the rainfall can be obtained in this manner. It should be remem- 

 bered, however, that these data represent in most cases town condi- 

 tions, not actual orchard observations. And, further, in considering 

 the elements of climate, such as moisture and temperature, with 

 respect to their influence on any plant, it is necessary to take into 

 account the condition of the plant in question at the time or during 

 the period in which the particular element prevailed. For instance, 

 peach buds when completely dormant may endure a certain low 

 temperature without injury. If, however, the same temperature pre- 

 vails after the buds have started in the spring or following a warm 

 period during the winter, they may be entirety killed. 



While the climatological data just tabulated may approximate 

 the conditions which prevail in the Piedmont orchards, they can not 

 be applied to the mountain region. Accurate data applicable to the 

 mountain orchards are as a rule even less readily obtained than 

 those for orchards in the Piedmont region. It is not unusual, how- 

 ever, as observed by some of the residents of the mountain districts, 

 for the temperature to drop considerably below zero during the 

 winter at some of the higher altitudes. The character of the native 

 growth indicates climatic conditions similar to more northern lati- 

 tudes. 



There are many local climatic factors which can be determined 

 only by a close study of the localities in question, such as danger 

 of or immunity from frosts, the usual course of local showers, and 

 many other features of importance. 



There is one feature noticeable in some portions of the mountain 

 region that is worthy of special mention. This is the "green belt," 

 " thermal belt," or "frostless zone," as it is variously called, which 

 extends in many places along the slopes of the Blue Kidge and its 

 spurs, with southeastern to southwestern exposures. Where this 

 belt occurs many kinds of vegetation remain green for a considerable 

 time after all vegetation both below and above has been killed by 

 frost. It is not until the severe freezes late in the season occur that 

 the plants in this belt are injured. Concerning this thermal belt 

 J. W. Chickering, jr., writing in the American Meteorological Journal 

 for October, 1884, quoting Silas McDowell, of Franklin, Macon 

 County, N. C, says: 



Amongst the valleys of the southern Alleghenies sometimes winter is succeeded by 

 warm weather which, continuing through the months of March and April, brings out 

 vegetation rapidly and clothes the forest in an early verdure. 



This pleasant spring weather is terminated by a few days' rain, and the clearing up 

 is followed by cold, raking winds from the northwest, leaving the atmosphere of a pure 

 indigo tint, through which wink bright stars; but if the wind subsides at night the 

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