PHYSICAL AND CLIMATIC SETTING 49 



frosts as well as the tempering influence of Lakes 

 Erie and Ontario over which the prevailing wind 

 comes into that region. This insures the better ma- 

 turity of the wood and buds which increases their 

 power of resistance. The greater uniformity of the 

 winter weather keeps them dormant and resistant. 

 The effect is especially noticeable on peaches. 



The smaller inland lakes are considered to have a 

 similar though smaller effect on the weather in their 

 immediate vicinity and their ameliorating effect is 

 said to be most noticeable on the eastern shore. 



The weather of the Long Island and Lower Hud- 

 son Valley provinces is similarly modified. This 

 ha.:; favored the development of the vegetable industry 

 around New York City. 



In the plateau province there may be a wide range 

 in the length of season between the valleys and nearby 

 hill regions. This difference is well illustrated by 

 Ithaca and Perry City within twelve miles of each 

 other in Tompkins County. 



Liability to frost is also determined by topographic 

 position in another way. As a result of the circula- 

 tion of air in response to differences in temperature, 

 the cold air settles into low pockets and deep flat 

 valleys where frosts are frequent. On the highest 

 points they are also likely to occur, due to rapid radia- 

 tion and cooling at night. Consequently, the regions 

 most free from frost are the intermediate elevations 

 having a fair slope so that there is free circulation of 

 air. The swamp and muck lands are generally liable 

 to unseasonable frost because of these relations. The 



