36 OREGON _ FARMER 



Change in Climate. 



In studying the various districts themselves, and as they are 

 shown in tables of results herein, the climatic conditions will be 

 found to play a very important part in the variation in production 

 observed. Since very misleading statements are often expressed 

 regarding "changes in climate" supposed to take place, it is well to 

 state here that the climate of any locality does not change. A very 

 common fallacy in new countries is the belief that the climate will 

 alter, rainfall increase and frosts decrease with the change brought 

 about by putting land under cultivation or irrigation, while in old 

 settled countries it is very commonly stated that the climate is 

 changing. Both of these ideas have been repeatedly proven untrue 

 by the most authoritative and indisputable records of accurate 

 weather observations. Precipitation and frosts in a region are not 

 altered by cultivation or irrigation. In very small confined local 

 areas, night temperatures may be slightly altered but never sufficiently 

 to be of practical importance as far as crops are concerned. Nor 

 does the climate grow steadily worse or steadily better. Weather 

 varies greatly from year to year but there is an average or normal 

 weather condition that may be depended upon to prevail the majority 

 of years. 



Climatic Considerations. 



The important climatic considerations as affecting the production 

 of a region are, normal total precipitation and its distribution 

 through the year, (especially during the seeding and growing and 

 harvest seasons), and frosts, (as regulating the length of season). 

 The effect of the Japan current on the westerly winds and the great 

 variation in the topography of the state are the chief factors 

 causing Oregon's unusual climatic features and the wide climatic 

 variations between the different regions. (Data for different 

 districts of the state are given elsewhere) . See page 65. Oregon 

 is largely free from the torrential rains which cause floods and injurious 

 soil erosion free from injury by hard and violent winds noted 

 for her cool nights in summer, and, in Western Oregon especially, 

 for the great mildness of all winter and summer temperatures and 

 the exceptionally long growing seasons. The rainfall varies widely 

 it is heavy on the coast, ample in the Western Oregon interior, 

 less in Southern Oregon, and scanty in the Columbia basin and 

 Central Oregon, increasing again in the Blue Mountain region. 

 The distribution of rainfall for spring seeding is good throughout 

 the state, and for fall seeding excellent, except in portions of the 

 Columbia Basin where it generally comes a little late. For the 

 harvest of hay and grain the conditions are ideal, but for summer 

 crops the precipitation is a little too light in the summer months 

 unless thorough cultivation is given. 



The temperature is mildest and the growing season longest on 

 the coast, mild and long in the Willamette Valley, shorter in Southern 

 Oregon as the elevation increases, still shorter in the Columbia 

 Basin and Blue Mountain region, and shortest in Central Oregon 



