FOREST AREAS AND SOIL WATER 
139 
sites and for sites representing a stage between these two; sec- 
ond, soil moisture determinations for forested and open sites. 
THE AREA 
The area chosen for these tests was in the “Backbone” State 
Park in northwestern Delaware county, Iowa. It is in a sec- 
tion of the state which was covered by the older continental 
glaciers, where there is still a large portion of native timber 
growth and where conditions do not approximate so nearly the 
prairie conditions of other parts of the state. The park area 
itself is rough in topography and typical of much of that country, 
which is not valuable for agriculture other than for grazing. 
Description of Sites . — Four main sites were selected upon 
which to locate the various stations as described in Table A. All 
of these were at one time covered with heavy timber growth. 
This has been entirely cleared from sites 1 and 3. Site 1 has 
been continuously grazed since the removal of the timber, while 
site 3 has been grazed only occasionally and is now reproducing 
a timber stand. A good layer of litter and decaying vegetable 
matter covers the soil on sites 2 and 4, both of which still carry 
a heavy stand of timber growth. 
EVAPORATION 
Column 1 Table A shows the location of all the various sta- 
tions. 
Evaporation readings were made at stations as follows : 
