TREES OP THE MISSOURI BASIN 
39 
of a forest even though the greater part of each season be favor- 
able to tree-growth, and the failure of the trees of course re- 
sults in the failure of the minor forest flora which in our terri- 
tory is essentially mesophytic. 
Annual Mean Temperature.^® 
Station 
County 
Years 
Degrees 
Fahrenheit 
Altitude, feet 
Sioux City 
Woodbury 
13 
47.7 
1,165 
Onawa 
Monona 
24 
32.07 
1,048 
Logan 
Harrison 
37 
48.7 
928 
Council Bluffs 
Pottawattamie 
6 
51.1 
990 
Glenwood 
Mills 
15 
51.2 
891 
Thurman 
Fremont 
6 
50.4 
Rock Rapids 
Lyon 
6 
28.0 
— 
Table Showing the Minimum Temperature for January and February, 
1904. 
station 
County 
Minimum tem- 
perature for 
January 
Minimum tem- 
perature for 
February 
Little Sioux 
Harrison 
—16 
—17 
—13 
—17 
Sioux City 
Woodbury 
Pacific Junction 
Mills 
—13 
— 5 
Thurman 
Fremont 
—13 
—19 
8 
Le Mars 
Plymouth 
—17 
Logan 
Harrison 
—17 
— 5 
Precipitation and temperature are important factors in the 
growth of trees. The average precipitation as given by Sage 
and Chappel covering a period of years between 1890 and 1903 
is shown in the following tahle.^^ 
22B. Shimek. Op. cit., p. 468. 
“Iowa section of the Climatological Service of the Weather Bureau. An- 
nual summary, December, 1909. 
“Iowa Weather Crop Service Rep. 1902 with appendix. App. 29. 
