62 EUCALYPTS CULTIVATED IN THE UNITED STATES. 
thriftiness in dry situations and during droughts are remarkable. In 
many situations in the Southwest, where, during the three years 1897 
to 1900, the annual rainfall was from 4 to 8 inches only, the Blue Gum, 
in most cases, maintained a thrifty growth. . 
These trees are resistant to both quite high and quite low tempera- 
tures. While the young trees will not usually endure a continued 
temperature much below 27° F., they will endure maximum tempera- 
tures of 100° to 105° F., if the air is not especially arid: they do not, 
however, endure maximum temperatures much above 105° F. in the 
dry interior valleys of southern California and southern Arizona. In 
southern Arizona they endure minimum temperatures of 18° F., but 
are severely injured by the dry winds of summer when the mercury is 
above 108° to 105° F. Several species of Eucalypts endure both 
lower and higher temperatures than these, but there are few species 
that do so well when subjected to extremes. 
Uses.—This species is the most generally useful of all the Eucalypts. 
It is especially useful as a forest cover. Being adapted to such a 
variety of soil and climatic conditions it can be used to cover a great 
variety of lands Baron von Mueller says: 
For mitigating the heat of the arid treeless regions, subject to high summer tem- 
perature, Eucalyptus globulus plays a most important part also. But the culture of 
the tree should be million jold. * * * The rearing of forests of our Blue Gum 
tree can be accomplished more cheaply and more easily than that of almost any 
other tree, while the return is twice or three times earlier than that of the most pro- 
ductive Pine or Oak forests, and this raising of Eucalyptus forests can be extended 
to regions in which most Pines and all Oaks would cope in vain with an almost rain- 
less clime, although Eucalyptus culture can never advance to cold zones. * * * 
Sterile land, unless it be absolute sand, will soon be transformed into a verdant and 
salubrious grove, more particularly so if substrata do not consist of impenetrable 
layers or outcrops of rocks. While quietly the forest advances, almost without 
expenditure and care, its wood treasures increase from year to year without taxing 
the patience of generations, and within less than half the lifetime of man timber of 
conspicuous dimensions can be removed after fuel has been provided annually long 
before, while the unpropitious original surface-soil will have been converted into a 
stratum oi fertility for agricultural or pastoral returns from successive storage of min- 
eral aliments brought up. 
In the Southwest this species has proved to be the most useful one 
to plant for wind-breaks and for shade. It is also the one that has — 
been planted most extensively for fuel and for timber. (Pl. XXIII.) 
It has been used for piles in several wharves on the Pacific coast with 
very satisfactory results. It is also the one that is used principally as 
the source of eucalyptus oil in California. 
The timber of this tree is of a rather pale color, is hard, heavy. and 
very strong and durable. It is fairly straight-grained and quite easily 
split. In Australia it is used for shipbuilding, for carriage making, 
and in the manufacture of agricultural implements. It is also used 
in bridge building, for telegraph poles, and for railway ties. In Cali- 
