FROST RESISTANCE OF EUCALYPTUS IN CALIFORNIA 423 



taking place almost entirely at the ends of the branches, was being 

 formed at that time. There were no adventitious shoots on the stems 

 or branches and no suckers were coming from the roots. An examina- 

 tion in August showed that in the five months intervening the trees had 

 produced a normal growth of 20 inches. 



Eucalyptus citriodora Hooker. Lemon-scented Gum 



Although the degree of cold that lemon gum can stand without seri- 

 ous damage appears to be limited, no mature trees in southern Califor- 

 nia have as yet been killed outright. In every case observed the lemon 

 gum was recovering from the damage received. Trees in Redlands 

 were the most severely injured. In one instance the owners, thinking 

 that their trees were dead, proceeded to cut them and dig out the roots, 

 while in an adjacent block the same species was recovering from the 

 freeze. At Smiley Heights the trees seen at a distance, even 10 weeks 

 after the freeze, appeared dead. A closer examination, however, 

 showed that they were putting out new shoots. Some of them were cut 

 back to within about 25 feet of the ground and sent out sprouts along 

 all sides of the trunk from within 4 feet from the ground to within a 

 foot of the cut surface. The largest sprouts were nearest the top. In 

 two cases the sprouts fairly covered the pollarded trunks, while in 

 others they appeared to be making very slow growth. 



In every nursery, as far as could be ascertained, the young lemon 

 gums had been killed outright before the lowest temperatures were 

 reached. 



Eucalyptus robusta Sm. Sz^'amp Mahogany 



After the freeze fears were expressed that all swamp mahogany had 

 been killed and the appearance of the region seriously marred. In 

 Redlands a number of trees were cut by owners who thought them 

 dead. After the freeze the leaves all turned brown and fell and many 

 branches were discolored. Two months afterward, however, the trees 

 were all in heavy foliage again and the avenues resumed their former 

 appearance. The sprouts resulting from the freeze were confined al- 

 most entirely to the tops. The normal spring growth appeared as usual. 



Younger trees in plantations were all defoliated, and the tips of the 

 smaller branches were killed back for from 6 to 12 inches. Sprouts 

 developed in large clusters on the upper part of the stem, but the 

 stronger and more vigorous growth came normally. In several places 

 where young trees had been set out the winter before the plants were 

 killed to the ground, and in these cases sprouts came from the root 

 collar. 



