Evening star. [volume] (Washington, D.C.) 1854-1972, 1914-09-05

cut surface by the use of creosote. This
chemical stands far ahead of any other
preparation for such use, the booklet
declares. The sterilization is followed
by a waterproof coating, preferably Of
coal tar. A single application. Of a
mixture of coal tar and creosote has
given good results. but the safer way
Is the use of the tar waterproofing
coat The mixture used contains about
one-fourth or one-third creosote.
Before cementing long cavity"
says the pamphlet, 1T is advisable to
place through 1t one or more bolts. so
as to hold the wood and cement more
firmly in place. A cavity two feet or
less in length will not usually require
a. bolt, but long cavities as a general
rule should be bolted every eighteen
to twenty four inches. Often single
bolt can be placed so as to support
both sides.
sary to place bolts at different angles
In any case a strip of uninjured cam
blum at least an inch wide should be
left between the edge of the cavity
and the bolt. On medium-sized trunks,
after deciding where the bolts can
half-inch bit, sufficiently long to reach
through the trunk and cavity, can be
used to bore the hole for the bolt. On
large, heavy trunks larger bit should
De used. f16GVy oval or rOunQ iron OF
steel washers about three times the
diameter Of the bolt should be counter
sunk into the wood by carefully cut
ting away the bark at both ends of the
hole with sharp gouge or chisel"
Shaping the Cavity.
The bottom and all other parts of a
cavity should be SO shaped, says the
author, that if water were thrown into
the cavity it would run out imme-
diately and none remain in the hollow
This is commonly called Drainage"
Another important point in shaping a.
cavity is to have the sides undercut
II possible, so as to hold the filling
firmly in place. Care should be taken.
however. not to have the wood at the
edges of the opening very thin, as this
promotes the drying out of the bark
and ,sapwood at these points.
After the cleaning and sterilizing the
next step is the filing of cavities. For
this a good grade of Portland cement Is
recommended Or asphalt may be used.
Tin, zinc and iron are of benefit in some
cases, but the use of cement properly
prepared so as to be Of the right con-
sistericy, has given best results in the de-
partment's experiments. says the report.
Regarding the cutting. the report says:
Usually an old decayed spot may be par
TALLY or wholly covered by new growth
Of wood and bark at the edges and the
visible decayed area be small as COM
pared with that which is hidden. In such
cases it is usually necessary to enlarge
the opening with the gouges and mallet
in order to make sufficient room In which
to use the gouges in the Interior. This
opening should not be any wider than Is
necessary, for reasons already stated in
discussing sapwood. but 1t may be suffi-
GENTLY long to reach all the decayed and
diseased heartwood with little or no ad-
ditional injury to the tree.
'If the decayed and diseased wood OK
tends some distance above or below the
external opening it is a common prac-
or below the main opening in order to
facilitate the removal of the diseased
wood. This results in one or more bridges
Of wood and bark spanning the long in
terror cavity.
'.As q general rule, tree surgery can