PROPAGATION OF TREES. 213 
quired for the production of healthy growth is to keep 
the weeds under, and the soil loose between the trenches 
with cultivator or spading-fork, and prevent the appear- 
ance of obnoxious growths among the young plants. 
Some varieties of plants require shading from the sun 
and protection from the first winter’s frost, and for this 
reason are sown in beds about four feet square, so as con- 
veniently to allow the construction of a frame to ward off 
any injurious influences which might naturally be brought 
to bear against the thrift of the young seedlings. The 
soil in these frames should be composted to the same de- 
gree of fineness and richness as that required in trench- 
seeding in the open ground; but this will depend en- 
tirely upon the variety which it is intended to nourish. 
No general rule can be applied, either for protection or 
richness of soil, as each separate species of tree has its 
own peculiarities in these respects, and thrives only 
when afforded a sufficiency of soil and climate according 
to its natural habit. 
The seed may be sown broadcast in these beds, and 
covered lightly with fine leaf-mould, after which the 
frame may be constructed about them, consisting of 
boards a foot or more in width, placed round the edges 
of the bed and covered by a lath screen or coarse mat- 
ting. The lath screen is considered the most convenient 
covering, as it admits the genial warmth of the sun to 
the plants without exposing them to its full influence. 
CUTTINGS. 
Propagating from cuttings is the mode employed in 
the production of certain species of frees, and when seed 
of other kinds cannot be readily obtained cuttings are 
used in their production. Though cuttings of some spe- 
cies of trees take a longer time to produce or emit roots 
than others, yet all kinds may be so propagated if al- 
lowed sufficient time for the formation of their roots. 
The root-producing substance, alburnum, or sap, partakes 
