62 EUCALYPTS CULTIVATED IN THE UNITED STATES. 



thriftiness in diy situations and during droughts are remarkable. In 

 many situations in the Southwest, where, during the three ,vears 1897 

 to 1900, the annual rainfall was from -1 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 usuall}' endure a continued 

 temperature much below 27° F., the}^ 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 

 dr}^ 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 103° 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 especiall}^ 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 oi' 

 the tree should be million fold. * * * 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 of 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. (PI. 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 In-idge building, for telegraph poles, and for railway ties. In Call- 



