433 JOUENAL OF FORESTRY 



growing in the Forest Service arboretum there, and, judging from 

 these, the tree is not very susceptible to frost, for less than half the 

 leaves show any sign of having been nipped. Normal growth from the 

 axillary buds was in evidence and was concentrated almost entirely on 

 the ends of the topmost branches. In the spring of 1913 the tallest 

 specimen of this species was 11 feet, with a diameter of 2^ inches. 



Eucalyptus saligna Sm. New South Wales Blue Gum 



Nine three-year-old trees of this species are at Del Rosa ; the tallest 

 7 feet. The 14-degree temperature killed about half the leaves on these 

 trees, but new normal growth developed in all instances. One tree put 

 out three sprouts from the root collar and was the only one to give evi- 

 dence of abnormal growth. The new growth after the freeze (which 

 started early in February) was caught in a frost, when the temperature 

 fell to 28 degrees ; but the trees recovered from this within 10 days and 

 new leaves and buds developed. 



Eucalyptus resmifera Sm. Red Mahogany 



In recent plantations, as well as in older ones, not a single tree of 

 this species was found killed to the ground, though 80 per cent or more 

 of the leaves and a large proportion of the small twigs were killed. 



Very few adventitious buds developed on the younger trees, and 

 those that did appear occurred within 2 feet of the ground or on the 

 lower branches. Normal growth also took place, however ; most of it 

 in the upper part of the crown. This new growth was extremely rapid. 

 Sprouts did not come out in clusters, as in the case of nearly all other 

 species, but were scattered singly or in pairs on the stem. 



The older plantations were affected in a similar fashion, but the 

 sprouts came out in clusters rather than singly, high up on the trunk, 

 in the crown, and on the branches. Normal growth was much more 

 rapid than sprout growth. In August the sprouts were apparently 

 dying. Where the temperatures were the least severe, the damage to 

 red mahogany was restricted to the defoliation of approximately half 

 the tree. 



Eucalyptus regnans Baker & Smith. Giant Gum Tree 



Giant gum is probably represented in the San Bernardino Valley only 

 by nine specimens of three-year-old trees at Del Rosa. These trees, 

 the tallest 9 feet and the smallest 4. were unaffected by a temperature 

 of 14 degrees. The examination of these trees in March did not dis- 

 close any frost injury whatever, and the seasoned growth, which was 



