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brace and support it. Accordingly the removal of the heart wood does 

 not necessarily result in the death of the tree. Death in such cases may 

 result from windbreak. Heart rot gains access to a tree through branch 

 stubs, through roots, or through deep scars and injuries. It often gets 

 a start in street trees through the dying back of a stub in the top caused 

 by poor pruning at the time of planting and subsequent neglect. It is 

 common practice to top back forest grown trees to a point where the 

 main stem is from one inch to three inches in diameter. The new growth 

 is apt to start several inches below the cut, thus allowing the end to die 

 and become infected. Such dead ends should be removed and the scar 

 painted. 



Sap rots usually result from the spread of heart rots or occur in < lying- 

 trees. They are serious since the function of the sap wood is to serve 

 as a transporting medium for the food material from which the wood 

 cells are built. By killing out this layer the circulation of sap is in- 

 terfered with and if the rot extends completely around the tree the host 

 may be killed. 



Heart and sap rots are prevented by careful pruning, followed by 

 covering the wounds with paint, tar, or creosote. All insect o-alleries 

 serve as a point of access for fungus spores. Such holes should be 

 drained and painted. 



There are three methods of treatment for cavities and diseased places 

 in shade trees. They are called the open cavity, cement filling, and 

 asphalt filling treatments. At the present time the tendency is to do 

 as much open treatment as possible. 



Excavating Rots. In repairing a tree affected by rot the first step 

 is to bore in at several places to locate the exact extent of the rot. It 

 may be feasible to excavate from one hole entrance or again two or 

 more may be needed. In cutting out decayed wood it is essential that 

 all the rot be removed. The so-called 'rots" often extend several 

 inches into apparently sound healthy wood. It ig frequently impos- 

 sible to tell whether the decayed portion has been entirely cut out, but if 

 the cavity is left open a subsequent examination will clear up all doubts. 



Excavating Tools. A mallet, a half round gouge, and two or three 

 chisels of various sizes are handy tools for this work. Large cavities 

 may be opened to advantage with hand axes. After all the decayed part 

 has been removed the bottom of the cavity should be provided with drain- 

 age to prevent water from standing there. It is not essential to have 

 the walls absolutely smooth, but they should not have large crevices that 

 may harbor insects. The mouth of the cavity should be made regular, 

 and where possible the shape should be oval, tapering toward the top 

 and bottom. This type of hole heals over quickest, while square ends 

 often result in dead areas adjoining the hole due to the failure of the 

 sap to properly nourish them. 



Painting. There are several good covering substances on the market 

 for painting over wounds. The creosote compounds penetrate well and 

 act as antiseptics. Tar is good, and roofing or asphalt paints are very 

 satisfactory. Ordinary house paint is better than nothing, but is apt 

 to crack, affording an opening for moisture and disease spores. Car- 

 bolineum is an excellent antiseptic paint. 



Sheet Metal. A modification of the open cavity treatment is the use 

 of sheet metal nailed across the cavity opening. In such cases the bark 



