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greater numbers or in larger specimens, or else by cutting back the quicker-growing 
ones. 
RvuLE 3. Shade-enduring kinds may be mixed with light-needing kinds when the 
latter are either quicker growing or are planted in advance of the former or in 
larger specimens. 
Ru we 4. Thin-foliaged kinds should not be planted in mixtures by themselves, 
except on very favorable soils, as in river bottoms, marshy soil, ete., where no 
exhaustion of soil humidity need be feared, or else on very meager, dry soils, where 
most shady trees would refuse to grow and one must make a virtue of necessity. 
RULE 5. The mixing in of the light-foliaged trees in single individuals is preferable 
to placing them together in groups, unless special soil conditions make the occupa- 
tion of certain spots by one kind, which may be better adapted to them, more desira- 
ble—as, for instance, the ash in a wet ground (slough). When a slower-growing, 
light-needing kind is to be grown side by side with a quicker-growing, shady one— 
as, for instance, Oak and Catalpa—a group of Oaks will have more chance to with- 
stand the shade of the densely foliaged Catalpa than the single individual. 
In the experimental plantings of this division a number of mixtures 
are given which are at variance with the rules above quoted. The pur- 
pose in view is to demonstrate the effect of various methods of mixture 
on the species used, and to make observations upon the growth of the 
more valuable timber species when surrounded by different shade influ- 
ences. There are more cloudless days in the plains than in the Eastern 
forest region, and this change in light conditions may affect the growth 
of tree species differently. Many combinations have therefore been 
made, the purpose in view being entirely experimental. 
PURE PLANTINGS. 
By pure plantings are meant plantations in which only one species 
has been used. Under the great majority of conditions’pure planting 
is not advisable, particularly so on highland. Where there is a con- 
stant supply of moisture, as near a running stream or in bottom lands 
with a porous subsoil, groves of a single kind of trees will frequently 
thrive as well as mixed groves. 
The same species, especially if a light-needing one, planted where 
there is a stiff subsoil, or in a drier locality, will grow well for a period 
of twenty to thirty years, when the trees will die rapidly, and at the 
time when they should be in the most vigorous health they fail com- 
pletely, because they were unable to keep out weeds and shade the soil 
sufficiently to prevent its drying out. 
At the Kansas Agricultural College there is a pure planting of Silver 
Maple, about twenty-five years of age, which began failing about five 
years ago, and in which there is now hardly a single healthy tree. This 
grove is on an eastern Slope, with rather thin soil on a limestone sub- 
soil—conditions not suitable for the species, which requires a deep, 
fresh soil. 
Mr. C. E. Whiting, of Monona County, Iowa, planted a grove of 
Silver Maples in 1873, which thrived until’they reached an average 
height of 60 feet. A few years ago they began to fail, and very few 
