CHICO FORESTRY SUBSTATION CLIMATE. 103 



fact, some of the orchards which have suffered most are several miles 

 east of Chico, and at a considerable elevation. Only a few species of 

 acacias do well here, and the eucalypts are also limited in their adapta- 

 tion to this region. The growth of the conifers is enormous, and that 

 of many oaks and ashes is also unusually great. The rainfall is excel- 

 lent; the summer heats are modified by the trade winds. 



Rainfall. The average rainfall of the Chico district, based on observa- 

 tions since 1870, is somewhat over 25 inches. It has fallen as low as 12 

 inches, and has risen to more than 50 inches, but these extremes very 

 rarely occur. The following table shows the rainfall for the past seven- 

 teen years, the average of which, disregarding 1901-2, which is not quite 

 complete at this date, is 26.64 inches: 



RAINFALL FROM SEPTEMBER, 1885, TO APRIL, 1902. 



c pn(8mi Total Period in which 



Rainfall. Some Rain Fell. 



1885-6 31.13 in. 7 months 12 days. 



1886-7 17.16 " 7 ' 28 " 



1887-8 14.49 " 7 



1888-9 _ 21.50 " 9 



1889-90 52.71 " 7 



1890-1 _ 23.46 " 9 



1891-2. 22.40 " 7 



1892-3 _ 33.50 " 7 



1893-4 _ 23.32 " 10 



1894-5 34.56 " 7 



1895-6 25.54 " 7 



1896-7 _ 22.44 " 9 



1897-8... 12.81 " 7 



12 

 11 

 5 



10 

 12 

 10 

 4 

 28 

 1 



20 

 2 



1898-9 18.45 6 ' 5 



1899-1900 24.89 " 7 " 1 



1900-1 27.22 " 7 " 22 



1901-2.... 1996 " 7 " 22 " 



There is a good deal of early summer rain in this region, lengthening 

 the season. The rains have commenced as early as August 30th, but 

 the usual time is in late September or early October. They have con- 

 tinued until July llth, in showers after April, excellent for many crops, 

 but injuring cherries, hay, etc. The rainless period is comparatively 

 short here, and the growth of all kinds of trees suitable to the climate 

 is therefore stimulated. No other portion of California with which I am 

 acquainted has shown such rapid growth of the native white oak ( Quer- 

 cus lobata), nor such large groves of second-growth trees springing up 

 since the American occupation, and this must be attributed in great 

 measure to the favorable rainfall. 



Temperature. The observations of the past twenty years give an aver- 

 age winter temperature of 46.6 Fahr., an average summer temperature 

 of 81.3, and an average annual temperature of 63.8. The lowest 

 temperature of the period was 18, and the highest was 115. 



The following table shows the temperature day by day during 1899, 

 1900, and 1901, as furnished by Colonel C. C. Royce, and kept on Rancho 

 Chico. These temperatures were taken from a point fifteen feet above 

 the ground, and the minimums therefore show from 5 to 8 lower than 

 would be the case if .taken in the town, on the plan of the Weather 

 Bureau, from the top of a high building. They were taken for agricul- 

 tural purposes, and show the actual conditions to which vegetation at 

 the forestry station and the adjacent district is subjected: 



