26 EUCALYPTS CULTIVATED IN THE UNITED STATES. 
up shoots that will reach a height of 75 or 100 feet in from six to eight 
years. Several other species make an almost equally rapid growth 
after being cut. The cutting may be repeated every few years for an 
indefinite period. 
Eucalypts are propagated only from seed. To this fact is due their 
comparative freedom from injurious insects and from diseases usual 
to exotics which have been introduced into America by cuttings or 
seedlings. Their dissemination throughout the world having been by 
seeds alone, the insect enemies and the parasitic fungi of their native 
home have been left behind. In America they have few insect enemies, 
and they are remarkably free from disease. 
THE TRUNK. 
The character of the trunk varies considerably. Of many species 
the trunk is erect and straight-grained; of others it is more or less 
curved and twisted. In the majority of species the trunk diminishes 
in size upward very gradually, being long and cylindrical. It is this 
characteristic that makes many of them so admirably adapted for 
masts, piles, bridge timbers, and telegraph poles. 
The bark of the different species shows great variety. In some it 
is very rough, while in others it is quite smooth. In many species its 
character changes considerably with age. The bark of all seedlings | 
is smooth, that of some remaining so permanently, that of others 
becoming more or less rough and furrowed as the tree grows older. 
Some rough barks are fibrous and stringy on the outside, while others 
are hard and brittle. Trees having the former kind of bark are com- 
monly known as stringy-barks; those having the latter, as iron-barks. 
Intermediate between the above two types is a bark, somewhat fibrous, 
but more or less scaly on the outside, like that of the American Ash. 
Of several species the bark of the limbs is much smoother than that 
of the trunk; and often, in the same species, the surface of the bark 
varies considerably, being modified by the soil and climate. The bark 
remains permanently on the trunks and limbs of some species, while 
from others the outer layer falls away freely in sheets or strips, leav- 
ing the fresh surface smooth and lighter in color. The surface of the 
bark of different species varies in color from light cream to dark brown. 
The matured wood of all species is hard—of some species very 
hard. Of many species it is tough and durable, resembling in this 
respect the wood of American oaks and hickories. The wood of some 
species is heavier than water. The wood varies a good deal in grain, 
being straight-grained and easily split in somespecies, while in others 
itis gnarled and splits with great difficulty. For this reason the 
various species furnish timber adapted to a great variety of uses. 
The color of the wood varies from clear white to a rich brown. 
