292 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



Treatment of Wounds on Frozen Trees. Reference has been made 

 in various places to the necessity of properly treating wounds on 

 frozen trees, both in the case of areas injured by the freeze and of 

 wounds caused in pruning. In several sections of the state, wood 

 rots were spread in the pruning and apparently caused considerable 

 damage. In almost all cases some material was used by growers to 

 cover cut .surf aces, such as grafting-wax applied warm, liquid grafting- 

 wax, white lead, or some sort of paint. It was found by Dr. Barrett 

 and Professor Fawcett that these did not stop the infection with the 

 wood rots spread by pruning. These fungi developed under the wax 

 or paint. In the treatment of the wounds, in case of trunk injuries 

 and comparatively large cut surfaces in pruning (limbs one-half inch 

 or more in diameter), the best treatment that can now be suggested 

 is painting these, when freshly cut, with Bordeaux mixture or Bor- 

 deaux paste* and a few days later following this by painting the cut 

 surfaces with asphaltum dissolved in benzine, which gives a hard 

 smooth finish that will last for a long period. Asphalt paint dissolved 

 in benzine (use no turpentine) can be purchased at paint stores. 



AFTER EFFECTS OF THE FEEEZE 



For six weeks or so after the freeze, there were no changes in the 

 appearance of the groves, which could be looked upon by the rancher 

 as encouraging signs. During this time the injury done to the bark 

 became more apparent day by day: green bark became dull in color 

 and then dark brown ; cracks opened wider ; and the leaves kept falling 

 except in some places where the freezing had been most severe. In 

 these places the dead leaves did not drop but remained hanging as if 

 they were frozen on. 



Appearance of New Growth. Toward the latter part of February, 

 however, the buds began to start, and new growth appeared in 

 abundance. This growth was not confined to parts of the tree which 

 showed no injury. Of course, there was much wood upon which no 

 new growth appeared, but new shoots sprang out from many branches 

 and trunks, which were so badly split that the owners were greatly 



* Bordeaux paste formula: Dissolve 1 pound of bluestone (copper sulfate) in 

 1 gallon of water in a wooden or earthen vessel. This can best be done by hanging 

 it in a sack in the top of the water. Slake two pounds of quicklime in about 

 one-half gallon of water. Some variation from these proportions may be made 

 without greatly changing the value of the paste. Stir together when cool, making 

 a light blue mixture about the consistency of whitewash. If the mixture turns 

 to some other color before being applied, it is an indication that something is 

 wrong. Mix up fresh each day or two, as the mixed paste tends to deteriorate with 

 age. It may be applied with a large brush as whitewash. 



