CALIFORNIA VALLEY CLIMATES 15 



and from dew in summertime ; winds occasionally strong, hot, and 

 desiccating in summer and cold in winter. 



Local Modifications. The term "valley climate" is broad, and 

 includes everything, away from the coast to a certain elevation on 

 the slope of the mountains. Certain small valleys protected from cold 

 northerly winds and from fog-bearing westerly winds and open to 

 the spring sunshine, have a forcing climate which produces the earliest 

 maturing fruit of the season ; earlier not only than the coast and the 

 mountain, as has been stated, but also somewhat earlier than adjacent 

 locations in the broad, open valley. Slight elevation, even on the 

 sides of small valleys, frequently secures freedom from winter frosts 

 and ministers to early ripening. Elevation above sea-level on the 

 rims of great valleys also secures similar results and gives rise to 

 thermal belts in which semi-tropical fruits are successfully growing 

 even as far north as Shasta County. On the floors of great valleys 

 moderating influences are secured on the lee side of wide rivers and 

 by planting on the river bank or on slightly elevated swells rather 

 than on the level, open plain. The river bottom lands of the great 

 valleys, though subject to severe frosts, are freer from the effects 

 of desiccating winds than the open plains; they are, however, more 

 favorable to the spread of certain blights than the plains. 



Some of the horticultural effects of valley conditions are as 

 follows : Early ripening and perfection of summer and autumn 

 fruits, owing to continual sunshine and dry air; forced maturity of 

 certain fruits, as apples for instance, which destroys character and 

 keeping quality; injury from sunburn and hot winds in summer, 

 which seriously affect both fruit and foliage of some varieties ; 

 occasional injury to tender fruits (semi-tropicals) and to young trees 

 of hardy fruits, which have been kept growing late in the season, 

 from low temperature, which sometimes is reached suddenly on the 

 floor of the valleys; freedom from some blights and insects which 

 are prevalent on the coast, but not from others. Many of these minor 

 troubles are, however, counterbalanced by the earliness, size, beauty, 

 and quality of certain fruits, and by the most rapid and successful 

 open-air drying of fruits, owing to high autumn temperature, the 

 freedom from summer fog, dew and generally from rain during the 

 drying season. 



FOOTHILL CLIMATE 



Foothill climate is usually considered as a modification of valley 

 climate. It has been shown that up to about two thousand five 

 hundred feet, on the western slope of the Sierra Nevada, the seasonal 

 temperatures are quite like those of the valley, but the rainfall in- 

 creases about one inch for each hundred feet of elevation. There 

 are, however, in the foothillls, places where early spring heat and 

 freedom from frost give very early ripening fruits, and other places 

 at the same elevation where winter temperature drops below the 

 valley minimum, and where late frosts also prevail. This is gov- 

 erned by local topography. In many of the small valleys among the 

 foothills, both of the Sierra Nevada and the Coast Ranges, frosts 



