One of the most promising chemicals is sodium arsenite. It can be used 

 to promote debarking if applied to a girdled band of exposed wood during 

 the natural bark peeling season. Killing action takes place in a matter of 

 days and bark loosening follows after several months. 



Sodium arsenite is toxic to plant and animal life alike. For this reason 

 it must be handled with caution. 



Another chemical, ammate, which is the trade name for ammonium sul- 

 famate, has been widely used but it is not as effective in killing certain species. 

 However, ammate is not poisonous. 2-4-D and 2-4-5-T used singly or in 

 combination are chemicals of proven value particularly in killing out shrubs 

 and the smaller trees. 



Application of Poisons 



There are many ways of applying poisons. In the case of small trees, 

 shrubs, and bushes, poisonous materials may be sprayed on. 2-4-D and 

 2-4-5-T are used as foliage sprays to kill vegetation which has to be cleared 

 from power lines. These poisons can also be used to kill small trees during 

 the dormant season. When so used they are called basal sprays as they are 

 applied on the lower part of the trunk and on those portions of the roots 

 which are exposed. 



When trees of more than two inches in diameter are killed, a common 

 practice is to cut through the bark into the wood with an axe or other tool 

 in such a manner that ragged frills are left, upon which the poison can be 

 deposited. The usual way of making these bark frills is to strike slanting 

 blows downward with an axe which tends to force strips of bark and sap- 

 wood away from the trunk. This type of cutting is continued around the 

 tree. A convenient height for frilling is just above the root swell. Chemicals 

 in either dry or liquid form can be used. 



Tree poisons are available at farm-supply houses in most sections of the 

 country. They are packaged in convenient form with full directions for use 

 and proper warning about handling those of a highly toxic nature. At the 

 present time thexe is no single chemical or method of application that can 

 be pointed out as best for killing brush and trees of all sizes. 



Where there are many stems per acre, as in the case of shrubs and brush, 

 a broadcast treatment is usually satisfactory. This involves the use of chem- 

 ical sprays which will cover the largest area at lowest cost. Where there 

 are fewer stems per acre as large as two inches in diameter, the so-called 

 basal spray may be best. Here again, the use of such sprays or methods 

 depends upon the unit cost. One advantage in basal spraying over the broad- 

 cast type is that selection of individual trees is possible. The better ones can 

 be saved and those unwanted killed. 



Whenever 2-4-D or 2-4-5-T are used separately or in combination as a 

 spray the spraying equipment should not be used for any other purpose. It 

 is nearly impossible to cleanse sprayers sufficiently for safe use after once 

 using these chemicals in them. A drawback to ammate solutions is that they 

 tend to rust metals to such an extent that thorough washing is always neces- 

 sary if the equipment is to be kept in usable condition. 



Killing Large Trees by Girdling 



In the next larger-size group, whatever method is used will take more 

 time owing to the fact that each tree must be treated individually. The present 



