FROST resistance; of eucalyptus in CALIFORNIA 425 



Eucalyptus crchra F. v. M. Narrozv-leaved Ironbark 



Narrow-leaved ironbark was found at Banning, Highland, San Ber- 

 nardino, and Del Rosa, where, as a mature tree, it withstood the lowest 

 temperatures reported. At Del Rosa, in the small sapling stage, it 

 withstood a temperature of 14 degrees above zero F. From the largest 

 tree noted (20 inches diameter and 80 feet tall) down to the smallest 

 three-year-old sapling at Del Rosa (6 feet in height and i inch in 

 diameter 6 inches above the ground) the damage was very slight. Only 

 a few leaves were tinged or nipped by the frost. The normal season's 

 growth appeared after the spring rains occurred, and since that time 

 the growth has been steady. 



The narrow-leaved ironbark is thus one of the most frost- resistant 

 of the eucalyptus planted in the San Bernardino Valley. 



Eucalyptus diversicolor F. v. M. Karri 



At Del Rosa, where the only karri trees were found, 5 per cent of 

 the three-year-old trees were killed outright by the cold, while the re- 

 mainder had been killed back to within about 8 inches of the ground. 

 The subsequent growth, however, has been very rapid. Sixty per cent 

 of the sprouts came from the root collar, there being very few sprouts 

 per tree. Reports received from nurserymen showed young stock to 

 be more frost-hardy than that of blue gum. The old trees, however, 

 appeared to be very frost-sensitive. 



Eucalyptus cornuta Lab. Yate 



The only Yate trees found were in the Del Rosa arboretum. Here 

 the three-year-old trees were badly damaged by the low temperature 

 of 14 degrees. All the top part of the plants was killed — leaves, twigs, 

 and stem — to within 14 inches of the ground. Sprouts appeared from 

 adventitious buds 10 weeks after the freeze and grew very slowly. No 

 record was obtained as to frost-hardiness of the species from the nur- 

 serymen. 



Eucalyptus corymbosa Sm. Rloodzvood 



Bloodwood is represented at Del Rosa by four trees, two of which 

 were killed outright. Roots and stem alike were badly discolored and 

 gave ofif a very disagreeable odor when cut. The other two trees sent 

 out adventitious shoots from near the ground, but the growth has been 

 very slow. 



