3870 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. 
INDIVIDUAL TREATMENT OF DISHASED TREES. 
Where valuable ornamental, shade, or orchard chestnut trees 
become infected in one or more spots their life and usefulness can 
be prolonged for several or for many years, depending largely upon 
the thoroughness with which the recommendations herein given for 
cutting out the cankers are carried out. Better results will be ob- 
tained with small, thin-barked trees than with large ones. 
The essentials for the work are a gouge, a mallet, a pruning knife, 
a pot of coal tar or good paint, and a paint brush. In the case of a 
tall tree a ladder or rope, or both, may be necessary, but tree climb- 
ers should not be used, as they cause wounds which are very favorable 
places for infection. Sometimes an ax, a saw, and a long-handled 
tree pruner are convenient auxiliary instruments, though practically 
all the cutting recommended can be done with a gouge having a 
cutting edge of 1 or 1} inches. All cutting instruments should be 
kept very sharp, so that a clean and smooth cut may be made. 
By cutting with the gouge into a diseased area a characteristically 
discolored and mottled middle and inner bark is revealed. All of 
this diseased bark should be carefully cut out for an inch or more 
beyond the discolored area, if the size of the branch will allow it. 
This bark should be collected in a bag or basket and burned. If the 
cutting is likely to result in the removal of the bark for much more 
than half the circumference of the branch or trunk it will probably 
be better to cut off the entire limb or to cut down the tree, as the case 
may be, unless there is some special reason for attempting to save 
the limb or tree. The fungus usually, though not always, develops 
most vigorously in the inner bark next to the wood. When the 
disease has reached the wood not only all the diseased bark and an 
inch of healthy bark* around it must be removed, but three or 
more annual layers of wood beneath the diseased bark must also be 
gouged out. Special care should be taken to avoid loosening the 
healthy bark at the edges of the cut-out areas. Except in the early 
spring, this is not difficult after a little experience in manipulating 
the gouge and mallet, provided the gouge is kept sharp. Small 
branches which have become infected should be cut off, the cut being 
made well back of the diseased spot. 
All cut-out areas and all the cut ends of stubs should be carefully 
and thoroughly painted with coal tar. A good grade of paint has 
been recommended by some authorities as superior to tar, but it is 
more expensive. If the tar is very thick the addition of a little 
creosote will improve it for antiseptic purposes as well as for ease in 
applying. If the first coat is thin a second one of fairly thick tar 
should be applied within a few weeks or months. Other coats should 
be applied later whenever it becomes necessary. . 
