114 INTRODUCTION TO BOTANY 
107. Problems of forestry. Most of the questions which 
the practical forester has to consider can be grouped under 
three heads: 
j. How to establish forests on areas naturally treeless or 
on tracts of perfectly cleared land. 
2. How to maintain existing forests for an indefinite period 
in the most productive condition. 
3. How to fell timber and remove it with the least possible 
damage to the trees that are left standing. 
In a book on general elementary botany only a few hints 
on these most important topics can be given. Every intelli- 
gent citizen, however, should at least know that the conserva- 
tion of our forests is highly essential, and should understand 
the general bearing which it has on our welfare as a nation. 
108. Forest plantations on treeless land. In such treeless 
regions as the prairies and the Great Plains it is often desir- 
able to establish belts of timber or considerable tracts of wood- 
land. This is done partly for shelter from winds and partly 
for the timber produced for local uses. The seeds may be 
planted where the trees are finally to stand, or young seed- 
lings may be procured from a forest nursery. The latter plan 
is the better, and it is well to have the young seedlings trans- 
planted once or twice before their final planting, to avoid the 
formation of long roots, the cutting off of which would check 
the growth of the tree. Both coniferous and dicotyledonous 
trees are much planted. Some of the most generally available 
conifers are the white pine, the Scotch pine, the Austrian pine, 
and several kinds of spruce. Among the desirable dicoty- 
ledons are cottonwood (fig. 96), silver (or white) maple, 
green ash, honey locust, hardy catalpa, red oak, and (in the 
warmer parts of the country) eucalyptus. In climates such 
as that of the lowlands of California, Hucalyptus globulus is 
the most rapid growing of hard woods, reaching a diameter of 
one foot and a height of one hundred twenty-five feet in ten 
years. To reach this diameter the white oak would require 
a hundred years. 
