836 TREES OF EUROPE AND AMERICA COMPARED. 
While the American forest flora has made large contribu- 
tions to that of Europe, comparatively few European trees have 
been naturalized in the United States, and as a general rule the 
indigenous trees of Europe do not succeed well in our climate. 
The European mountain-ash—which in beauty, dimensions, and 
healthfulness of growth is superior to our own *—the horse- 
chestnut, and the abele, or silver poplar, are valuable additions 
to the ornamental trees of North America. The Swiss arve or 
zirbelkiefer, Pinus cembra, which yields a well-flavored edible 
seed and furnishes excellent wood for carving, the umbrella- 
pine, + which also bears a seed agreeable to the taste, and 
which, from the color of its foliage and the beautiful form of 
its dome-like crown, is among the most elegant of trees, the 
white birch of Central Europe, with its pendulous branches 
almost rivalling those of the weeping willow in length, flexi- 
bility, and gracefulness of fall, and, especially, the “ cypresse 
funerall,’ might be introduced into the United States with 
great advantage to the landscape. The European beech and 
chestnut furnish timber of far better quality than that of their 
American congeners. The fruit of the European chestnut, 
though inferior to the American in sweetness and flavor, is 
ous in the Old World, even in the case of trees not generally receiving special 
eare. This multiplication of varieties is no doubt a result, though not a 
foreseen or intended one, of human action; for the ordinary operations of 
European forest economy expose young trees to different conditions from 
those presented by nature, and new conditions produce new forms. All Euro- 
pean woods, except in the remote North, even if not technically artificial for- 
ests, acquire a more or less artificial character from the governing hand of man, 
and the effect of this interference is seen in the constant deviation of trees 
from the original type. The holly, for example, even when growing as abso- 
lutely wild as any tree can ever grow in countries long occupied by man, pro- 
duces numerous varieties, and twenty or thirty such, not to mention inter- 
mediate shades, are described and named as recognizably different, in treatises 
on the forest-trees of Europe. 
*JIn the Northern Tyrol mountain-ashes fifteen inches in diameter are not 
uncommon. The berries are distilled with grain to flavor the spirit. 
+ The mountain ranges of our extreme West produce a pine closely resembling 
the Huropean umbrella-pine. 
