12 FIELD OPEKATIONS OF THE BUREAU OF SOILS, 1912, 



growth seldom occur before the usual date of the last killmg frost. 

 Certam other fruits, such as peaches and grapes, may be forced into 

 bloom by a few warm days early in the spring, and these may suffer 

 severely with a subsequent lowering of temperatures. The dates of 

 killing frosts in the spring are extremely variable in different portions 

 of the valley, owdng to differences in elevation and the conditions of 

 air drainage. For tliis reason the data given in the table are applica- 

 ble only to a small part of the valley immediately adjoining the upper 

 part of the town of Hood River. 



The prevailing winds are from the west, as the gorge of the Colum- 

 bia River plays the part of a gigantic flue and affords a passage for 

 the wind from the cool coast country^ eastward toward the heated 

 interior. The velocity of the wind is least during the winter season, 

 when the temperatures on the coast and in the interior are more 

 nearly equal, and greatest in the spring and enrlj summer, when the 

 temperature in the plains section east of the mountams is much 

 higher than that along the coast. The usual drift of the wind from the 

 coast toward the interior is the prmcipal factor in maintaining the 

 low temperature of the summer season and in preventing excessively 

 low temperatures during the -winter. It is onl}" when the normal 

 conditions are disturbed that there is any noticeable movement of 

 air from the interior toward the coast, and whenever this occurs the 

 extremes of temperature for the season follow. In the summer 

 season the winds from the heated plains to the east cause the ther- 

 mometer to rise above 90°, and this heat will persist for one to three 

 or four days. With the Avinds from the interior during the winter 

 season the tem])erature drops, but in a few days the \\TJid swings 

 into the west and the severe temperature is replaced by a noticeably 

 warmer period. 



The average climatic conditions which exist in these valleys are 

 such that the production of berries, deciduous fruits, and forage 

 crops that are adapted to a cool, temperate climate will be profit- 

 able, providing, of course, that suitable locations are chosen. 



AGRICULTURE. 



The first settlers in these valleys occupied the comparatively level, 

 elevated floors of the valleys and also the narrow bodies of alluvial 

 soil along the Columbia River. The absence of accessible markets 

 limited the activities chiefly to stock raising. In the districts men- 

 tioned grain could be growm for hay, and the stock were ranged over 

 the adjacent lands of the valley and on the mountain and hill slopes, 

 where, when the forest was not too thick, a good growth of grass 

 afforded grazing during the greater part of the year. 



A few trails and wagon roads led from the settlements to distant 

 points in the valleys, but access to outside markets was available only 

 by steamers on the Columbia River. The town of Hood River and 



