280 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



or two sides, with the idea that by thus cutting out a narrow strip 

 of bark growth could be hastened, were much oftener found with split 

 and loosened bark after the freeze than trees where the bark had been 

 left intact. The demonstrations of this point were so general that the 

 method of scoring young trees will probably not 

 be practiced in the future. 



Some ranchers had practiced rubbing neats- 

 foot oil on the bark of trees which were affected 

 with gum disease. Occasionally a man was 

 found who had put this oil on the bark of 

 healthy trees, reasoning that if neatsfoot oil 

 was good for trees suffering with gum disease, 

 which it is not, it should be a good preventive 

 measure. In some of these places, where large 

 bearing lemon trees that had been in good 

 health but had had the trunks painted with 

 neatsfoot oil as a preventive against gummosis, 

 the oiled trunks had all of the bark killed, while 

 trunks which had not been oiled had their bark 

 unharmed. 



Although the observations as to greater frost 

 injury to sick trees were in most cases from a 

 few isolated trees in individual orchards, where 



the majority of trees were healthy, the same 

 Tig. 10. Two-year-old , ,, , , , , , _, ,. 



Eureka lemon on which general results have been noted between entire 



bark had been slit longi- groves in the same section, and under practi- 

 tudinally (scored) with ,, , ,.,. , . , 



knife before the freeze cally the same condition as to elevation and 



and which the freeze temperature. Although immediately following 



further seriously injured ,, T.,-, j-a> 



though the foliage of the the freeze there was little difference in appear- 



tree remained uninjured. a nce between groves in various states of vigor, 

 Scoring the bark in this ,, , . ,. ,, , ,,, 



way does no good and tne greater recuperative powers of the healthy, 



may cause serious injury. W ell cared for, clean orchards than of dirty, 



Photo by Tylor, July 5. . , , -, i_ i. 



1913 ' sickly, poorly cared for groves has been very 



marked. 



Influence of Trunk-Section of Top-Worked Trees. A very inter- 

 esting difference which was brought out by the freeze was that of the 

 resistance offered by trees which had the same kind of tops but dif- 

 ferent kind of trunks. Of course most of the citrus trees have the 

 top and the trunk the same, as they are budded low. But there are 

 many groves in which the trunk of the tree is lemon and the top 

 orange, the trees having been worked over from lemons to oranges at 



