Page 26 



BETTER FRUIT 



Recommendations for Winter -Injured Trees 



By W. S. Brown, Chief of the Division of Horticulture, Oregon Agriculture College 



THE damage that resulted to Oregon 

 orchards during the middle of De- 

 cember from widespread low tempera- 

 tures was rather spotted in its severity, 

 some locations not suffering as much 

 as the extreme cold would seem to 

 indicate. 



The most serious damage seems to be 

 in the region of the free immediately 

 above the snow line, taking in the up- 

 per part of the trunk and the main 

 limbs. It is indicated by a discoloring 

 of the bark, the cambium layer and in 

 some instances, the outer part of the 

 wood. The fender growing point and 

 sometimes the entire inside portion of 

 the fruit spur may be affected. Com- 

 bined with this bark and wood injury 

 many buds are affected, especially on 

 the sweet cherries and pears. 

 Cause of Injury. 



The chief cause of the injury, which 

 is usually found to extend entirely 

 around the free, is the combination of 

 low temperature, coupled with the pres- 

 ence of considerable sap in the lower 

 part of the trees at least. Another con- 

 tributing factor which was very serious 

 was the heat generated on the south 

 and southwest sides of the frees by the 

 sun's reflection on the snow. This 

 caused a drying out of that portion of 

 the bark and an injury much worse in 

 some cases than is found on the north 

 side of the tree. 



It is found from this work that there 

 is a great deal of difference in the^ 

 severity of the injury, due to several 

 causes, among them the condition of the 

 frees at the time of freezing, and the 

 variety and the location of the orchard. 

 All gradations in injury are found. 



In a few instances portions of the 

 free above the snow line are entirely 

 killed, in others the bark and wood is 

 not so seriously hurt but that it will 

 probably recover, though the crop will 

 not set for next year. In other cases 

 some of the limbs of the tree, especially 

 those on the south and southwest side 

 may be killed and the rest of the tree 

 may recover. Portions of bark may die 

 on the sides of some limbs, necessitating 

 the cuffing off of this bark later and 

 the subsequent painting of the wood, or 

 bridge-grafting, or both. 



Seriousness of Damage. 



If is not possible to tell at present 

 just how badly injured the trees are. 

 Shortly after the freeze the division of 

 horticulture of the college station sent 

 out a great number of letters to differ- 

 ent growers throughout the state ask- 

 ing them to send samples of injured ma- 

 terial fo the college. A great many 

 limbs, twigs and buds have been sent 

 in for examination. Some of the twigs 

 containing buds have been placed in 

 the greenhouse in wafer, to see if they 

 have vitality enough to open the buds 

 and function properly. Tissues from 

 the larger limbs were given careful mi- 

 croscopic examination. 



Naturally the question comes up 

 what treatment can we give these trees. 

 The answer is that we can do very little 

 except to give nature as good a chance 

 as possible to recoup herself. 



Pruning Not Advised. 



Every fruit grower is wondering 



what is best to be done about pruning. 



The horticultural division recommends, 



after having examined a great many 



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March, ip20 



samples of injury and after several 

 members of its staff have visited injur- 

 ed orchards in widely different parts of 

 the state, that little or no pruning be 

 practiced at this time. It will be better 

 to leave the trees unpruned until April 

 or May, and then notice the conditions 

 of the individual trees before pruning. 

 The reasonableness of this course is ap- 

 parent when it is considered that some 

 of the limbs that might be pruned out. 

 at this time may be needed next spring 

 to take up the growth of the tree, espe- 

 cially if the other branches have been 

 injured. Beside this fact the uninjured 

 buds in the top of the tree are needed 

 to pull up the sap to the tops of the 

 twigs and limbs in the early spring. The 

 more of these buds that are cut off, the 

 less will be the pulling power. If this 

 sap can be brought up to all parts of 

 the tree, it will prevent the tree from 

 drying out and will give the cambium 

 a much better chance to recover. 



Then, of course, there is the question 

 of expense. If the tree has been killed 

 by the freeze, it is only throwing away 

 money to prune it at this time, espe- 

 cially when such pruning can do no 

 good. Further, large cuts that are made 

 by removing branches of good size in 

 the trees expose considerable tissue to 

 drying out at this time and therefore 

 injure the circulation of the sap. 



Pruning would seem permissible only 

 when the trees had been neglected in 

 previous years and had become too 

 dense. In that case a very light thin- 

 ning out might be permitted at this 

 time if the tree has the appearance of 

 being injured only slightly. If it is 

 very severely injured no pruning should 

 be done. In late spring or early sum- 

 mer, all cuts of any size, from one inch 

 in diameter on up, should be carefully 

 protected with some material such as 

 white lead and raw linseed oil mixed 

 with shellac or with a Bordeaux paste. 

 In many respects the Bordeaux is the 

 best as it keeps fungi from entering at 

 this point. 



Just what type of pruning the tree 

 will need in late spring will depend 

 upon the injury it has received. A state- 

 ment will be issued on this subject by 

 the experiment station horticulturists 

 next .spring. 



Decrease in Nitrate Production 

 A decrease of about 50 per cent oc- 

 curred in the production of nitrate in 

 Chile during November, 1919, as com- 

 pared with the corresponding month 

 last year, according to the United States 

 Consul in the Antofogasta. The exports 

 showed a still greater decrease. 



Canning and other methods of food 

 preservation are receiving an impetus 

 in all parts of the United States. This 

 means that waste in the products of 

 the farm and orchard will be reduced, 

 wider markets created and the supply- 

 ing of isolated districts with a greater 

 variety of diet. It should also have an 

 influence in reducing the cost of living. 



WHEN WRITING ADVERTISERS MENTION BETTER FRUIT 



