FROST RESISTANCE OF EUCAI^YPTUS IN CALIFORNIA 419 



was killed, while the remainder of the tree was practically uninjured. 

 The lowest temperature at the nearest ranch was 17 degrees. 



Though many trees examined were almost entirely defoliated by the 

 frost, the great majority lost only about 60 per cent of their leaves. 

 The rest, however, were badly frostbitten about the edges. The twigs 

 and the smaller branches evidently were not killed, as normal growth 

 began eight weeks after the freeze. Adventitious shoots were found 

 on a large number of trees. The majority of these started well out 

 toward the end of the branches rather than on the main stem. 



Where the temperature did not fall below 20 degrees, as at Rialto, 

 Ontario, and Mentone. very few of the leaves were frosted and no 

 adventitious sprouts formed, all the growth being normal. 



This would tend to show that while the species can withstand tem- 

 peratures 12 degrees below the freezing point without much damage, 

 temperatures lower than this result in the defoliation of the tree and 

 the development of adventitious buds. 



Eucalyptus amygdalina Lab. Giant Bucalypt 



The giant eucalypt is classed as one of the trees which suffers rather 

 severely from the cold, but which can endure freezing temperatures 

 and yet recover. All the leaves were killed on the trees of the giant 

 gum, and with them some of the larger branches, as well as many of 

 the smaller twigs. Sprouts developed in about nine weeks after the 

 cold, and though the general symmetry of the trees has been spoiled, 

 they are apparently as healthy as before. Its graceful form has brought 

 the species into favor for shade and ornament, and for these purposes 

 the trees have been ruined. Nothing is known of the action of the low 

 temperatures on nursery stock or coppice. 



Eucalyptus viminalis Lab. Manna Gum 



The only damage to manna gum observed was that about 20 per cent 

 of the foliage had been nipped more or less seriously, and that here 

 and there a few twigs were so badly frosted that they did not recover. 

 As with all other species, the younger trees suft'ered more than the 

 older ones. No sprouts followed the freeze. 



The coppice of the manna gum about two years of age was not hurt 

 beyond a few frosted leaves, while coppice a year old was almost de- 

 foliated. Young plants set out the winter previous were completely 

 defoliated. The subsequent growth, however, does not show any evi- 

 dence of injury. 



