44 EUCALYPTS CULTIVATED IN THE UNITED STATES. 



water in the ground at their roots; second, their corresponding power 

 of giving off fresh from their foliage the water thus taken up by their 

 roots; third, the exhalation from their leaves and other parts of vola- 

 tile oils, which affect the climate not onlv directlv but by ehanpfino- 

 the oxygen of the atmosphere to ozone; fourth, the purification of 

 germ-infested matter by the foliage dropped upon the ground or in 

 pools of standing water. From the combined action of these four 

 characteristics is seems reasonable to believe that the trees would be 

 beneficial to many climates. 



It is not necessary to determine, however, before setting Eucalvpts, 

 whether they have a pronounced beneficial effect upon climate or not. 

 The}- certainly do not injure a climate. They serve so many other 

 useful purposes that the question as to their effect upon climate may 

 be waived, and the planting- of them still go on from other motives. 

 The belief that they improve climate has served a useful purpose 

 regardless of the facts in the matter. The planting of trees is such a 

 desirable thing that it matters little what the motive for planting them 

 be, provided they get planted. Eucalvpts may confidently be grown 

 for a forest cover, for wind-breaks, for shade, for timber, for fuel, 

 for the oil and the honey they furnish, and if, at the same time, they 

 improve the sanitary condition of the region in which they are grow- 

 ing, the reward of the planter will be so much the greater. 



PROPAGATION AND CARE OF EUCALYPTS. 

 DIFFICULTIES IN GROWING SEEDLINGS. 



Eucalypts are less easily propagated in America than most other forest 

 trees. This is due in part to the smallness of their seeds and the infer- 

 tility of many of them, and in part to the fact that each species 

 requires or at least prefers, certain peculiar climatic conditions. Few 

 grow spontaneously in the Southwest yet, and none do so freely. The 

 Red Gum and the Blue Gum are occasionally found growing spontane- 

 ously from fallen seed, and at Mr. Cooper's ranch near Santa Barbara 

 Red Gum seedlings were seen by the writer in abundance under trees 

 in shaded canyons, and in washes below the trees. (PL VIII.) Mr. 

 Cooper also pointed out trees about a foot in diameter that had grown 

 from volunteer seedlings. Southwest of Los Angeles, near the ocean, 

 where the temperature is even and the atmosphere more humid than 

 farther inland, young seedlings often appear in the groves of Blue 

 Gums, and this occurs in similar situations in central California, being- 

 very noticeable on the universit}^ campus at Berkeley. On the Min- 

 ncwawa ranch, near Fresno, seedlings of Eucalyptus radix appear under 

 the trees in abundance each spring, and are used by the owner for 

 planting. (PI. VIII, b.) 



In some regions species which grow fairly thriftily when once started 



