44 BULLETIN 479, U. S. DEPARTMENT OF AGRICULTURE. 
spruce thrives much better if shaded during the second year at the 
Boulder, Savenac, and Monument Nurseries. The same is true with 
bigtree at the Savenac, Douglas fir at the Pocatello, and western red 
cedar (Thuja plicata) and Norway spruce at the Wind Kiver 
Nursery. At the Converse Flats Nursery 2-0 Jeffrey pine and 2-0 
incense cedar are shaded, but it is not known to be necessary. At the 
Page Creek Nursery the shading of sugar pine in its second year in 
the seed beds has proved undesirable, because the seedlings when 
shaded reach a size larger than is convenient for transplanting. 
EOOT PRUNING. 
Root pruning is the cutting off of the lower part of the roots of 
seedlings without removing them from the beds. Its object is to 
promote the growth of lateral finely branched roots and a stocky 
top (Pis. IX and X). It is especially worthy of trial for species 
with very pronounced taproots or with any species when field plant- 
ing is to be attempted with seedling stock. It is a practicable opera- 
tion only when the seedlings are grown in drills or in narrow broad- 
casted strips. It has not been tried extensively at Forest Service 
nurseries, and the results of the practice are not yet conclusive. 
One type of primer that has been used is a large butcher knife, 
which is thrust into the ground between the rows at an angle of 
about 45° and then drawn along so that its edge severs the roots 
about 6 inches below the surface of the soil. Another is a heavier 
blade about 12 inches long which is bent below the middle and has 
its lower cutting end slanted someAvhat downward. It has two han- 
dles at right angles to each other and about 8 inches apart. Before 
starting to prune with this tool the soil between two rows of trees is 
cut with a spade, then the bent end of the priming blade is dipped 
into the soil at the end of a row and drawn along as in shaving at 
any desired depth under the surface. The tool most commonly used 
is a sharp spade, which is driven into «the soil at an angle along one 
or both sides of a row of seedlings and thus cuts off a portion of the 
roots. The advantage of using a spade is that it can be operated 
more rapidly than the other tools and can be used even in stony soils. 
The other tools are not very efficient under any condition, and are 
especially impractical in stony ground because they are quickly 
dulled. In Australia root pruning with spades is practiced even 
where broadcast sowing is done in long strips 12 to 13 inches wide. 
Two men with sharp spades work together. Facing each other on 
opposite sides of a strip, each thrusts a spade into the soil on his side 
of the row, guiding it at an angle of about 45° downward and toward 
the center of the strip. The spades meet, practically insuring the 
severance of the lower portions of the roots of all seedlings in the 
strip. 
