22 ORCHARD FRUITS IN VIRGINIA AND OTHER STATES. 



While the mountain soils at points south of Virginia are more 

 variable than those of the Piedmont region, they generally possess 

 the loose, friable character of the mountain types which are found 

 in the Virginia section of the region previously referred to. In some 

 places a heavier clay soil than is usually the case in Virginia is 

 found at considerable elevations. 



THE CLIMATE. 



In the Encyclopedia Americana, Moore defines climate as the sum 

 of the atmospheric conditions as recorded for a long period of time, 

 or u the totality of the weather." Weather is the physical condition 

 of the atmosphere at a given time or for a limited period. We 

 speak of the weather of to-day or of last week, and the weather 

 which prevails in a place for an indefinitely long period of time 

 makes the climate of that place. Climate includes, as stated by 

 Moore, " atmospheric pressure, temperature, rainfall, snowfall, time 

 and frequency of frosts, extremes of heat and cold, direction and 

 velocity of wind, the amount of air that flows from the different 

 points of the compass, amount and intensity of sunshine, humidity 

 and transparency of the atmosphere, and its electrification." 



It has been said that climate affects the health, happiness, and 

 well-being of people more than any other factor that enters into their 

 environment. If this is true of climate in its relation to man, who 

 is able, in a measure, to protect himself against adverse climatic 

 conditions, it is obvious that it has a still wider application in relation 

 to plant life, with which there is no self-protection except by slow 

 adaptation. 



That climate, or some element of it, is an important factor in con- 

 trolling the distribution of plants, both cultivated and wild, is readily 

 apparent. For instance, those fruits which are characteristic of the 

 Temperate Zone are not able to endure the low temperature of the 

 extreme north or the relatively high temperature of lower latitudes. 

 The same is true of the fruits which are native to tropical or 

 subtropical regions. Moisture is equally as potent as temperature 

 in determining the range of plant growth, whether it be orchard 

 fruits or wild plants. This is seen in the behavior of plants during 

 severe drought or of plants native to a humid climate as they approach 

 their limits of growth in the direction of arid or desert regions. 



Between the extremes of temperature and moisture, together with 

 the other elements of climate, there is every possible gradation, and 

 the infinite number of combinations of temperature and moisture are 

 manifested in some degree in terms of plant life. At one extreme 

 there is an abundance of heat and a minimum of moisture, producing 

 desert conditions where only specialized forms of plant life can endure. 

 At the other, a maximum of both heat and moisture, where the lux- 



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