eased trees to bring them back to
health or to prevent them from infecting other healthy trees nearby. To
bring the trees back to health implies that the disease can be cured.
This is not always true for the tree may be already nearly girdled, when
the disease is first noticed. A tree taken in time, however, may have
its life prolonged indefinitely though it may have the blight in some
portion of it every year. More particularly does this apply to valuable
ornamental and orchard trees.

Prof. J. Franklin Collins, Forest Pathologist in the Department of
Agriculture in Farmer's Bulletin No. 467 on "The Control of the Chestnut
Bark Disease" gives the following: "The essentials for the work are a
gouge, a mallet, a pruning knife, a pot of coal tar, and a paint brush.
In the case of a tall tree a ladder or rope, or both may be necessary
but under no circumstances should tree climbers be used, as they cause
wounds which are very favorable places for infection. Sometimes an axe,
a saw, and a long-handled tree pruner are convenient auxiliary
instruments, though practically all the cutting recommended can be done
with a gouge with a cutting edge of 1 or 1-1/2 inches. All cutting
instruments should be kept very sharp, so that a clean smooth cut may be
made at all times."

All of the discolored diseased areas in the tree should be removed.
Small branches or twigs nearly girdled are best cut off. Cankers in the
main trunk or on limbs should be gouged out. Carefulness is the prime
requisite in this work. If the disease has completely killed the
cambium, the bark should be entirely removed as well as several layers
of wood beneath the canker. By frequent examination, however, diseased
spots may be found on the tree where the mycelium of the fungus is still
in the upper layers of the bark. It is not necessary then to cut clear
to the wood, but the discolored outer bark may be removed and a layer of
healthy inner bark left beneath the cut. The sap may still flow through
this layer. The border of the diseased area is quite distinct, but
cutting should not stop here but should be continued beyond the
discolored portion into healthy bark, at least an inch. The tools should
be thoroughly sterilized by immersion in a solution of 1.1000 bichloride
of mercury, or 5 per cent solution of formaldehyde, before cutting into
the bark outside of the diseased area. Experiments have shown that a
gouge or knife may carry the spores into healthy bark a