FOREST PLANTING IN THE EASTERN UNITED STATES. 19 
are likely to have one or more of the advantages cited. The prin- 
cipal species in each mixture is named first; and where they take 
equal rank the fact is indicated by an asterisk (*): 
L.- Cottonwood and silver maple. 11. White pine and hard maple. 
2. Cottonwood and Norway spruce. 12. White pine and red oak. 
3. Cottonwood and white spruce. 13. Black walnut and white spruce. 
4. Cottonwood and green ash. 14. Old open stands of black walnut 
5. * European larch and white pine. underplanted with white pine. 
6. * European larch and red oak. Many of the old groves, particularly in 
7. European larch and white spruce. Iowa, are of soft maple. These may be 
8. * European larch and Norway spruce. gradually replaced by underplanting 
9. White pine and Scotch pine. with white spruce and removing the 
10. * White pine and Norway pine. maple. 
PROTECTION. 
INSECTS. 
The locust borer has completely destroyed many plantations of 
black locust; the white-pine weevil kills the leading shoot of white 
pine; the gipsy and brown-tail moths defoliate the hardwoods, par- 
ticularly the oaks, and in some cases have attacked conifers; while 
the sawfly has defoliated and killed much of the native larch and has 
attacked also the Kuropean larch. Before setting out any trees the 
prospective planter should communicate with the Bureau of Ento- 
mology of the Department of Agriculture, or with the State experi- 
ment station, in order to find out whether insect enemies of the species 
he proposes to plant are prevalent in the neighborhood. At the first 
sign of insects in an established plantation the owner should likewise 
communicate with the Bureau of Entomology to ascertain the best 
methods of combating them. 
FIELD MICE AND RABBITS. 
Young trees are sometimes girdled by field mice and rabbits. 
Where these pests are numerous it 1s almost impossible to prevent 
them from eating the bark of trees during the winter when green food 
of other kinds is absent. [f the grass around the tree is killed by 
cultivation there will be less danger from field mice, since these work 
largely under the grass covering. Poisoning is not always an efficient 
method of getting rid either of mice or rabbits; and poisoned food 
may kill some valuable domestic animal. 
WIND, SNOW, AND FROST. 
High winds often break or twist off the trees in a plantation. Such 
damage may be avoided to some extent by planting wind-firm species 
around the edge of the plantation, or by spacing the trees more closely 
on the windward sides. 
