112 INTRODUCTION TO BOTANY 
was to devise ready means of getting rid of the trees which 
covered the land (fig. 9+). A large part of the territory ex- 
tending east and southeast from the Great Plains region to 
the Atlantic and the Gulf of Mexico was forest-covered. 
Now that these im- 
mense primeval forests 
have been destroyed, 
never to be renewed 
in their original luxu- 
riance, we are coming 
to realize that in re- 
moving them the early 
settlers put an end to 
an almost unlimited 
source of income, and 
greatly injured the soil 
and climate of large 
areas. Some of the land 
had to be cleared in 
order to make tillable 
fields to grow bread- 
stuffs for the earliest 
settlers, but it is unfor- 
tunate that the clear- 
ing process was so 
well-nigh universal. 
105. Pure and mixed 
forests. Some forests 
are composed almost 
entirely of a single kind of tree, like the long-leaf pine 
growth of figure 229. A few of the hard-wood trees, as the 
birches, oaks, and maples, are not infrequently found growing 
nearly unmixed with other trees. More frequently, however, 
two or more kinds of conifers grow intermixed in the same 
forest, and the hard-wood trees are still more likely to occur 
with several kinds associated. Thus we find in the same 
Fic. 94. A ‘deadening’; trees killed by gir- 
dling near the base to clear the land for corn 
Photograph by United States Forest Service 
