36 RHE FOREST TREE CULTURIST. 
desirable. Such a tree will be produced, but when, or by 
whom, the future will unfold. 
When a really fine sport or variety has been produced, 
no time should be lost in multiplying it, as there is always 
danger of losing the original; and if this should occur, 
then all is lost, unless we have propagated others from it. 
Now there are several ways of propagating such trees, but 
I shall mention only three, viz., Layering, Budding, and 
Grafting. 
LAYERING. 
This mode of propagating is almost as natural as that 
of seeds, as we see many plants that increase in this man- 
ner. Whenever the branches come in contact with the 
earth they emit roots; these layers throw up shoots which 
form plants, trees, or shrubs, and their branches again 
bending to the ground repeat the process, and so on indef- 
initely. But with those trees of which we shall treat in 
the following pages, very few, if any, would increase in 
this manner unless assisted or compelled to do so. The 
principle, or, more properly, the theory, of Layering may 
be explained as follows: 
A tree absorbs plant-food through its roots (this being 
always in the liquid form) ; it is then carried up through 
the alburnum (or what is commonly called the sap-wood) 
to the buds and leaves; it is there assimilated chiefly by 
the leaves, and the more volatile portions are given off; it 
then returns downward through the inner bark, and be- 
tween it and the wood depositing a thin layer of alburnous 
matter, which becomes soon after fully formed wood. Now 
