! First Aid To Wounded Trees 



A Department for the Advice and Instruction of Members of the American Forestry Association 



By J. J. Levison 

 City Forester of New York City 



Simple Methods of Preventing and Treating Injured Bark a Suitable Work for 



the Winter Months 



EVERY owner of an estate with trees on it has the 

 problem of tree wounds to consider. Every city 

 has streets with horse-bitten trees on them and 

 everyone owning even a single tree may some day find its 

 bark injured by the milkman's horse, by the neighbor's 

 automobile or by some mischievous school boy. 



When the bark is thus injured, a tree can no longer 

 produce the proper amount of foliage or remain in a 

 healthy condition very long. The reason for this is clear 

 when we stop to consider the nature of the most important 

 tissue of a tree the " cam- 

 bium layer " and note 

 how it becomes affected by 

 such injury. The cambium 

 layer is a thin tissue located 

 immediately under the bark. 

 It must completely envelop 

 the stem root and branches 

 of the tree. The outer bark 

 is a protective covering to 

 this living layer, while 

 practically the entire in- 

 terior wood tissue is com- 

 posed of dead cells and 

 merely serves as a support- 

 ing skeleton for the tree. 

 The cambium layer is the 

 real growing part of the 

 tree. It is the principal 

 part which transmits the 

 sap from the base of the 

 tree to its crown; it is the 

 part which causes the tree 

 to grow by the formation 

 of new cells, piled up in the 

 form of rings around the 

 heart of the tree, and it is 

 also the part which pre- 

 vents the entrance of in- 

 sects and disease to the 

 inner wood. 



From this it is quite evi- 

 dent that any injury to the 

 bark and consequently to 

 the cambium layer just be- 

 neath it will not only cut 

 off a portion of the sap 



CAUSED BY A HORSE BITE 



This tree, unprotected by a wire guard, was first injured when a horse chewed 

 the bark. The owner of the house whose front porch it shades could have 

 healed the wound by using a few cents' worth of coal tar and creosote, and 

 putting up a guard. He failed to do so, the wound spread, disease attacked 

 the tree, and this is its condition now. 



supply and hinder the growth of the tree to an extent 

 proportional to the size of the wound, but will also 

 expose the inner wood to the action of decay. 



It may be a small wound and may appear unimportant, 

 but if neglected it will soon commence to decay and carry 

 disease and insects into the tree. The tree then gradually 

 becomes weakened, hollow and dangerous, and its life is 

 doomed unless repairs are made. 



If the wound is dressed in time recovery is certain; 

 or if a suitable guard had been placed around the trunk 



of the tree before the 

 injury occurred, serious 

 damage could have been 

 avoided. 



The most serviceable 

 guard is made of wire net- 

 ting, 3^-inch mesh, No. 16 

 gauge and cut to a height 

 of six feet. There are 

 many other forms of tree 

 guards used; some more 

 elaborate and expensive 

 than others, but none more 

 efficient. The wire netting 

 guard has the advantage 

 over the others in adapting 

 itself to the tree when it 

 grows in thickness. 



In spite of efforts to 

 protect the bark of trees, 

 bruises, cuts and tears 

 occur, and in all such cases 

 the wound must receive im- 

 mediate and careful atten- 

 tion. Any attempt to force 

 the loose bark to grow 

 back to the tree will fail. 

 In dressing the wound the 

 rough edges of the injured 

 bark should be cut smooth 

 and the exposed wood cov- 

 ered with coal-tar. Coal- 

 tar by itself or in mixture 

 with creosote has an anti- 

 septic as well as protective 

 influence on the exposed 

 wood. Not only for these 

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