Portion of a pole from a red pine tree treated with sodiutn arsenite tab seven 

 months earlier. The path of chemical action is seen by the parallel lines on 



the post. 



Summary 



Killing of unwanted trees is effectively accomplished through the use of 

 chemicals. Sodium arsenite not only kills but in addition causes separation 

 of the bark from wood when introduced into living trees. 



Sodium arsenite has one characteristic which tends to limit its use. It 

 is toxic to human beings and wildlife. During the past three years a new 

 technique has been under examination to determine whether it is possible to 

 inoculate unwanted cull trees with toxic materials sufficient to kill them and 

 to leave them standing in the woods. 



Using ordinary blotting paper as a medium for absorbing sodium arsen- 

 ite, small tabs one-half by two inches are treated and dried. These tabs con- 

 tain approximately one-half gram of poison. A special tool is used to create 

 a pocket between bark and wood of the tree so the tabs can be inserted. 

 This tool is a small bark-peeling spud similar to a slightly bent chisel. When 

 it is forced straight through the bark a vertical slit is started which readily 

 opens when it is pried back with the spud. Then the spud is slid between 

 wood and bark for about two inches. One of the tabs is applied in the edge 

 of the slit, the spud is withdrawn, and the tab forced into the bark pocket. 

 More than 15,000 trees have been treated in this manner. Results show that 

 pine trees up to 4 or 5 inches in diameter and from 1.5 to 30 feet high may 

 be killed with only one tab. However, if the top is limby and there are many 

 heavy branches, it is much safer to insert one or two more tabs since the 

 time involved is only a matter of a few seconds. 



Hardwood trees may be killed by using the same method. However, 

 because of the irregular branching habits of hardwoods with the tendency to 

 form spreading crowns, it is necessary to use more insertions per tree then 

 is the case with pine. Another difference between hardwood and softwood trees 

 is that the softwoods can be treated throughout the year, while the bark on 



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