418 JOURNAL OF FORESTRY 



To sum lip, blue gum, though damaged by frost, recovers rapidly, 

 making new growth from the auxihary buds and sending out adven- 

 titious shoots as well. It should be ranked among the most frost-hardy 

 trees of the genus. 



Eucalyptus rostrata Schl. Red Gum 



Examination of over 200 red gums in the San Bernardino Valley did 

 not disclose a single dead tree, though many at first glance appeared 

 dead. After 12 weeks or so, however, normal growth started, showing 

 that the 18 degrees temperature did not kill the tree, but merely in- 

 hibited the growth for the time being. 



In several rows of shade trees individual variation in susceptibility 

 to frost was very noticeable. On some trees all the leaves were dry 

 and brown, giving them a dead appearance, while here and there in the 

 row was a red gum free from injury on one side, but with the other 

 side showing evidence of heavy frost. Occasionally a tree would 

 exhibit no damage beyond a few frost-nipped leaves. All the trees in 

 these rows were of the same age and had received the same treatment. 



Many trees on which the leaves had been frozen were putting out 

 shoots from various portions of the stem, the bunches appearing at a 

 distance like witches-brooms or mistletoe. Several trees were cut down 

 and these developed vigorous sprouts from the stump. Suckers formed 

 at the base of the trees and less frequently along the trunk. 



Bushy trees sent up twice as many sprouts as did the taller, more 

 erect ones, about 60 per cent of the sprouts coming from 2 to 6 inches 

 below the surface of the ground. 



In plantations one and two years old 85 per cent of the trees were 

 killed to the ground — a proportion much larger than in the old planta- 

 tions. Sprouts came from the root collar in all but one instance. 

 Where the trees had been covered with burlap during the cold period, 

 only a few leaves were killed, and in addition to the normal growth 

 sprouts had also developed. 



Though in one and two year old plantations the trees evidently can- 

 not withstand temperatures as low as 18 degrees, red gum, like blue 

 gum, on the whole withstands frost well and recovers quickly. 



Eucalyptus polyanthcma Sch. Australian Beech 



In its resistance to the cold the Australian beech also resembles blue 

 gum. Not a single tree of the species was found killed to the ground. 

 The most serious damage noticed was in a depression near the Santa 

 Ana wash, where the tallest branch of a tree approximately 8 years old 



