Treatment of Large Trees with Impregnated Paper Strips 



Large trees as well as small ones can be killed by inserting impregnated 

 paper strips into bark pockets. However, in the case of larger trees it is 

 necessary to make a number of insertions at properly spaced intervals around 

 the tree trunk. In the case of trees with a single stem, like the white pine, 

 satisfactory killing can be obtained by spacing the insertions four or five 

 inches apart. If a tree has numerous large branches in the crown, a spacing 



This is the equipment for killing trees with treated tabs. The picture shotcs 

 the spud, tab, and pointer, with the tab partly inserted in the bark pocket. 



of three inches would prove more satisfactory. This spacing is sufficient to 

 kill single trees growing in the open. An advantage of using such a method 

 is the assured success of killing by increasing the number of insertions. Also, 

 it is not necessary to make them all at the same height. Frequently defects 

 are found which would make it quite difficult to continue at the same level. 

 This is avoided by working either above or below the defect. In some cases 

 it may prove advantageous to stagger the insertions to be sure of com- 

 pletely treating a given tree. Bark loosening follows this practice. 



Reaction of Various Species 



As growth habits vary among the species, the reaction to chemical 

 treatment also varies. For example, white pine is killed quite easily, while 

 the birches show a somewhat higher resistance. Also, there is considerable 

 difference in the ease of peeling. For this reason, it takes a little longer to 

 make bark pockets in some trees than others. Red maple may be classified 

 as mechanically easy to treat. White oak would fall in the medium or moder- 

 ately difficult class, while black oak, which has a thick tough bark, would be 

 among those classed as difficult. 



It is quite common to see branches with green leaves scattered through- 

 out the crowns of treated hardwood trees, while the remaining foliage is dead. 

 These may persist for several months or possibly through a second growing 

 season. 



8 



