“PROPAGATION OF TREES. 215 
When planted in the open ground, cuttings should be 
so placed uprightly to nearly their full length that only 
an inch or two of their tops will be visible above ground. 
They are usually planted in rows of two to four feet 
interval, and two to four inches between plants in the 
length of the row ; but the distance between plants will 
chiefly depend upon the object for which they are being 
raised. 
Evergreens, being of a more tender nature than decid- 
uous trees, require greater attention for their successful 
production, and are chiefly grown from seed, except when 
it becomes necessary to multiply or preserve a particu- 
lar species or variety of species, in which instance they 
are propagated from cuttings or layers. They all, or 
nearly all, require artificial heat for their production, 
and for this reason are usually raised in hot-beds. 
In the instance of cuttings of evergreens being placed 
under frame after selection in the fall, the debarring of 
the heating influence of the sun from them by shade be- 
comes a necessity, so as to prevent an unseasonable or 
untimely growth of leaf, and allow for the prior devel- 
opment of the roots. This is owing to the decreased 
temperature requisite for the production of the root as 
compared with the warmth necessary for the growth of 
leaves. 
The cuttings of evergreens are usually placed in rows, 
at six inches apart, and the soil firmly pressed about 
them to about one half their length, which is generally 
from two to three inches. 
LAYERING. 
The method of layering has been obtained by observa- 
tion of nature’s growth, and has been established upon 
the fact of reproduction by the emission of roots from 
branches inserted in earth, under the same law which 
governs the growth of cuttings; though in layering, as 
in cuttings, the sap, which is the principle of growth in 
