‘150 FLORA OF WINNESHIEK COUNTY. 
consequent clogging of our streams with sand and mud. It is 
superior to any aggregation of cultivated or pasture plants for 
the reason that it is not removed to leave the soil bare during a 
large part of the year, as is the case with cultivated crops, and 
it is not eaten or tramped upon by cattle as in the | case of 
pastures. Moreover, through long adjustment. to existing con- 
ditions the native plants are perfectly adapted to the various 
surfaces upon which they occur, and they have become more 
pliant under the varying moods of our uncertain climate. They 
are, therefore, more certain of persisting, and thus ‘continuing 
their benificent influence. In a rough country the dangers from 
erosion and desiccation are great, not only to the land itself, but 
to the streams and water-courses. The steeper slopes should 
never be cleared of their covering of native vegetation, either by 
cultivation or by pasturing, for not only will they not be profit- 
able, but they will be a menace to better lands and to valuable 
springs and streams. 
But aside from these uses to which all our native plants lend 
themselves more or less readily, many of them more directly, and 
therefore more appreciably, affect the interests of man. Among 
the questions to which this usefulness of plants gives rise may 
be mentioned the problems of the forests, weeds, ornamental 
plants, medicinal plants, and consideration of rusts, smuts and 
other fungi which attack plants. The last subject has received 
much attention locally from Mr. Holway and will not be dis- 
cussed here. 
I. The Forest Problem. 
Originally not less than one-fourth of the surface of Winne- 
shiek county was covered with forest. This was sometimes 
‘secant, as upon the rocky slopes and drier hill-tops, or consisted 
of trees of but little value, as upon the narrow lower bottom 
lands. Here, as elsewhere, the forest was developed chiefly upon 
poorer soils. The sandy alluvial bottom lands, the rocky slopes, 
the gravelly or clayey hills—these formed the favorite habitat 
of trees. Even where a veneer of rich soil and leaf-mould 
appeared it was the effect rather than the cause of the forest. 
The forest prevented erosion; it retained moisture which made 
easier the disintegration of both organic and inorganic mater- 
