Copyright
Massachusetts Agricultural Experiment Station.

Bulletin - Massachusetts Agricultural Experiment Station (Volume no.379-398) online

. (page 67 of 77)
Online LibraryMassachusetts Agricultural Experiment StationBulletin - Massachusetts Agricultural Experiment Station (Volume no.379-398) → online text (page 67 of 77)
Font size
QR-code for this ebook


certain wounds and giving other supplementary treatment from time to time.
No list of suggestions could provide for all of the problems which will be encoun-
tered in individual tree operations, but by intelligent planning many costly dis-
appointments may be avoided.



TREE PROTECTION AND IMPROVEMENT PRACTICES

Although the variety and sometimes the extent of defects found in trees during
these studies might appear to be cause for alarm, any exaggerated fears of a tree-
less future should be allayed by the predominance of relatively sound and vigor-
ous trees. Moreover, many of the defects can be treated with appiopriate reme-
dial measures.

Municipal Trees Planted on Private Property. In the General Laws of Mass-
achusetts, provision is made for the Use of public funds for planting trees on
private property under prescribed conditions. Chapter 87, section 7 reads:



24 MASS. EXPERIMENT STATION BULLETIN 397

"Towns may appropriate money to be expended by the tree warden in planting
shade trees in public ways, or, if he deems it expedient, upon adjoining land, at a
distance not exceeding twenty feet from said public wajs for the purpose of
improving, protecting, shading or ornamenting the same; provided, that the
written consent of the owner of such adjoining land shall first be obtained."

Some tree wardens who have availed themselves of this provision of the law
report satisfactory results. No definite recommendations on the desirability of
planting trees on private property can be furnished, however, since conditions
vary widely in different communities. It sometimes happens that in areas where
narrow tree belts obtain, dwelling houses have little, if any free space as frontage.
Nevertheless, it would be well for tree wardens to explore all possibilities for
planting on private property in order to improve local tree conditions as far as
practicable.

Disease and Insect Control. It is not feasible to give control practices in detail
for the individual fungus diseases and insect pests observed. Diagnoses made from
specimens submitted to the Experiment Station will be reported whenever the
cause for the trouble can be definitely ascertained from laboratory examination.
Standard spray programs for the protection of foliage constitute the minimum pest
control measures that should be accorded trees.

Physiological Troubles. Physiological troubles of trees may be revealed by
the presence of small leaves or early yellowing and loss of foliage. Progressive
weakening, following disease, repeated insect infestation, and faulty transplant-
ing often result in certain physiological dit^orders. Inadequate food and water
relations are also common sources of trouble.

Compensation for lack of water during extended periods of drought may be
made by adequate watering of the soil about tree roots. If necessary, holes may
be drilled as in the application of fertilizer discussed below. Plant foods may
likewise be made available by addition of fertilizer to the soil about the feeding
roots, the amount required being dependent upon indiv'dual cases.

A satisfactory technique for introducing fertilizer into the soil includes the
drilling of holes about 18 inches deep and 2 feet apart, in the ground approxi-
mately under the limits of branch spread, or closer in the case of small, round-
headed trees lacking extensive feeding roots. The fertilizer is then inserted in
the holes, leaving the upper two inches for the replacement of soil. In determin-
ing the location of feeding roots of spiry trees, holes should be drilled beginning
at a distance about half the height of the tree away from the trunk and extending
in concentric circles to the limits of the roots.

The value of decaying organic matter, Such as well-rotted manure worked
into the soil at the rate of 15 to 20 cubic feet to 100 square feet of soil, should not
be overlooked in choosing a satisfactory general utility fertilizer. Unfortunately
local conditions may often make its use impracticable. However, when manure
is used it should be mixed thoroughly with the soil or a manure and soil mixture
should be introduced into holes in the same way as prepared fertilizers. At times,
roots under turf or in hard-packed soil may not be satisfactorily reached by
ordinary methods and aerating the soil in a cultivation program may be advisable.
Plowing the surface of the ground about a tree permits many advantages when
this practice is feasible. Fertilizers such as nitrate of soda, at the rate of 2 to 5
pounds for a medium-sized tree, and sometimes small quantities of lime may be
applied in the spring on the surface of plowed ground. Trees, such as oaks or
black and red spruce, which require an acid soil, are to be excepted.



TREE PROTECTION 25

Raw bone meal is a good fertilizer for most trees and may be applied either
on a plowed surface or in drilled holes. It becomes available slowly and appears
to do no injury even when used in large quantity. In applying all nutrients care
should be exercised not to overfertilize trees, else root burning may result and
more harm than good be accomplished From the fertilizers applied to he soil,
only those substances which are water soluble and can be absorbed by the root
hairs will have direct nutritional value. Hence, the presence of water is always
necessary in any successful fertilizing program. The retention of water and other
substances in the soil may be facilitated by the application of mulches. Such
practice is of particular importance in the case of evergreens.

Treatment of Wounds. Wounds on limbs and trunks of trees occur in a variety
of shapes and sizes. Those which result from the fracturing of a branch usually
have irregular and jagged margins. All wounds which can be shaped so that the
longer axes are parallel to the grain of the wood and which may be brought to
points at the extremities, are likely to heal more satisfactorily and to appear less
ugly than wounds not so treated. Final cuts of the wound margin should be made
so as to provide opportunity for callus growth (Fig. 5, B) and for drainage of
water.

When the outline of the surface to be treated has been definitely determined,
all rough and loose edges of bark should be removed with a sharp chisel, and
shellac applied with a small brush. The shellac will prevent drying out of the
narrow exposed moist layer of the inner bark. When this step has been carefullj'
completed, the wood surface of the wound should be made smooth and treated
with creosote, creosote oil, or other sterilizing agent; and with coal tar, asphalt
or other materials for protection. Creosote is inflammable and should not be
permitted to come into contact with an open flame. The creosote should be
applied only to the cut wood surface, with particular care to avoid the living
inner bark previously covered with shellac.

Good wound dressings or paints are possible substitutes which may be used in
a single apjilication provided the precautions previously outlined are observed.
Asphalt without creosote is an excellent protective covering for wounds. The
necessity of applying it hot doubtless explains why it is not more widely used.
An emulsion of asphalt and water is obtainable commercially and the use of this
preparation eliminates the necessity for heating. This material may be applied
in the same way as wound paint. The water soon dries, leaving an asphalt
covering.

The application of tar mixtures and creosote may cause severe injury to cer-
tain trees including magnolias, tulip-trees, and ornamental Primus species. For
these, other treatment is advisable, even though kss permanent in character,
and the following sterilizing and protective materials are sometimes used: liquid
wax, shellac, corrosive sublimate (bichloride of mercury), copper sulphate, spar
varnish, grafting wax, good commercial Bordeaux paste, Bordeaux powder mixed
with raw linseed oil, and water glass (sodium silicate).

In applying all protective coatings, care must be taken not to cover the un-
injuied bark about the wounds. Frequently, recoating of treated surfaces may
be necessary after a year's time, and blistering, cracking, or checking should be
corrected as soon as detected. Careful attention to these details may preclude
additional serious injury. In all cases, individuals contemplating the use of
materials on trees should inform themselves thoroughly concerning .the nature
of these materials and their proper handling, including the need for precautions
against possible injury to persons and property.



26 MASS EXPERIMENT STATION BULLETIN 397

Small wounds on slender branches do not ordinarily require protection, but
may be treated on valuable trees as a precautionary measure. When pruning
operations include so many tmall branches that treatment of all cut surfaces is
impossible, a safeguard for prompt healing is the careful use of a sharp hand or
pole piuner. In using an ordinary hand pruner with a curved blade, especially
on surfaces which are not to be treated with a protective covering, care should
be taken to hold the pruner so that the supporting base may bruise only the dis-
carded twig, Pruning hooks should be Uied only with considerable caution.

In making secure one's position while treating wounds in remote parts of trees, it
is often necessary to resort to the use of ropes. Experienced workers use ropes
extensively both while pruning and while treating tree wounds. The amateur
may frequently find that he is able to remove branches without the aid of ropes,
but they may be necessary to establish a safe position before engaging in extensive
wound treatment activities. The wearing of spurs, however, is never advise ble
in operations where the tree being treated is to be retained.

Pruning. Pruning is an important part of any tree improvement program
and may be accomplished at almost any season of the year when practicable.
In spring, when tree growth is most active, wounds inflicted during pruning tend
to heal more rapidly than at other seasons. However, bleeding is most copious
at this time, and loss of sap may somewhat weaken the trees as well as prove a
nuisance along streets and highways. For these reasons, excessive bleeders, such
as birch and maple, should always be pruned later in the season. Pruning when
the tree is in full leaf also has advantages in that dead and weakened parts are
then more obvious; and street and park trees are often pruned in winter when
spraying and other tree work programs are less pressing.

Whether the pruning work to be accomplished is simple thinning, extensive
trimming, topping, or pollarding, the technique of removing branches should
receive careful attention. On large limbs the first operation should be a cut made
with a saw on the under side of and somewhat less than half way through the
limb at approximately one foot from the ultimate pruning point (Fig. 12, A).

This should be followed by a cut on the upper side of the limb about two inches
farther out than the lower cut. Cuttmg with the saw should be continued until
the limb falls (Fig. 12, B).

A third cut made at the ultimate pruning point will remove the stub and leave
a clean cut surface of minimum size for sterilizing treatment and at the same
time promote a rapid callus growth (Fig. 12, C).

An attempt to complete the cutting in one operation on the upper side of the
branch will most frequently terminate unhappily, in an ugly enlarged wound
surface which will not callus over but will enqourage slime flux and defy satis-
factory later treatment.

Following storms, the prompt pruning of broken branches is essential in treat-
ing damaged trees. A saw which makes a wide cut is the best implement to use
in removing large branches. A strong sharp knife, a mallet, and a chisel will com-
plete the necessary instruments for removing accessible limbs. Bark or wood
which is splintered or loosened should also be removed with a sharp cutting
implement and the same protection against infection should be employed as in
the case of wounds.

Doubtless there will be instances in which all efforts to restore symmetry to
a storm-injured tree by pruning will fail. In such cases, severe pruning of the
f-ntire top of the tree, or pollarding, may be the best solution to the problem.
Most trees respond to pollarding in ^ome degree, and certain trees, like willows,



TREE PROTECTION 27

re&pond readily. In the course of time a nearly normal tree symmetry may be
developed by gradually reshaping the outline of profuse dense growth, and later
the tree's symmetry may be further improved by grafting if this practice proves
necessary. The result will commonly be the production of a dense head growth.
To a limited extent, this growth is often an f fifective contribution to the landscape.

Cavities. Certain general suggestions for the repair of cavities have alieady
been indicated. In special cases, complete treatment involving excavation,
sterilization, bracing and filling may be desirable, but it is most doubtful whether
an inexperienced worker is ever justified m undertaking to complete the entire
series of operations independently. In many cases, cavity enlargement can be"
checked by removing the obviously diseased wood and sterilizing and protecting
the exposed surfaces. It is almost impossible to eliminate all infected wood, but
debris and decayed tissue should be removed so as to expose a reasonably sound
and smooth wood surface which can be treated with antiseptics and protected
with wound dressing as already indicated. Careful consideration should be given
to the matter of the ultimate shaping of cavities in order to prevent the accumula-
tion of small reservoirs of water.

Mechanical Support. Any one of a variety of factors may indicate the need
for supplying add-tional mechanical support in trees. Specifically, attention
has been directed toward the following conditions of a tree and the environment
which make bracing advisable: decay, split crotches, weakened sharp-pointed
crotches, borer infestation, injured or pruned roots, poor or limited shallow root
systems, profuse top growth, proximity of damageable property, exposure to
strong wind, or loss of sheltering structures.

Considerable progress has been made recently by professional tree workers and
students of mechanics in the matter of bracing trees. Experimentation and ex-
perience have pointed out certain errors in early work (Fig. 13).

The use of steel rods as rigid braces with or without washers and nuts is com-
monly termed bolting of trees. In cases where parts of a tree must be drawn
together for bolting, the hole bored for a prescribed screw rod should be larger
than the screw rod. Therefore, washers and nuts must be used on both ends of
the rod. For other purposes it is evident that holes drilled for screw rods should
be rod size or smaller. Holes smaller than rod size should be drilled when washers
and nuts are not used on ends of screw rods. In this case dependence is placed
upon the grip of the screw rod in the self-threaded channel. When the size of
the hole drilled to receive the screw rod is identical with the size of the rod,
washers and nuts should be used on both ends of the rod. Screw rods serve in
crotch bolting, holding limbs together or apart, and cavity bracing. Also, as
"lip bolts", these rods draw together a long split or frost crack in trunk, branch
or cavity. Specific conditions will determine the number and location of screw
rods needed to insure the relative safeness of trees.

Steel cable instead of rigid rods is often used for bracing trees. A simple
method of cabling employs the fastening of a lag hook or e3'ebolt into each of the
two limbs forming a crotch so that the hooks or eyes face each other. The hooks
or eyebolts are then tied with steel cable. Where lag hooks are used, provision
should be made so that a final quarter turn will make the cable secure.

When trees require additional structural support, guying may solve the prob-
lem. In such cases wires are appropriately affixed to the tree and connected
with four strong posts set firmly in the ground on the north, east, south, and
west sides. If the guying is temporary, broad bands of leather or other strong
material are sometimes wrapped around the tree and supporting wires attached.



28 MASS. EXPERIMENT STATION BULLETIN 397

In the case of permanent guying, however, two eyebolts may be placed on oppo-
side sides of the tree trunk, one about six inches above the other and two wires
fastened to each.

Bridge Grafting. An injured part of a tree to be bridged by a graft should re-
ceive as preliminary treatment the same protection given any other wound.
In the spring, at which time the grafting is to be performed, the wound should be
inspected and the adjacent bark cut back evenly with a Heavy pruning knife to
provide the wound with edges of tightly fittmg, healthy tissue.

The young shoots or scions to be used in bridging the wound should be in a
healthy condition but completely dormant. To injure dormancy in scions,
pruned from the tree being treated or a similar one, it is advisable to cut twigs
about the diameter of a lead pencil to the desired length before the buds swell in
the early spring and store them under conditions which will prevent drying out.
A good method is to bury them on the north side of a building where warming of
the soil in spring is delayed. A protective covering wrapped about them will pre-
vent direct contact with the soil and a board over all will insure against water
soaking of the scions in the event of seepage into the ground during heavy rains.

Immediately prior to their use, scions should be sharpened or beveled by long
sloping cuts in order to form thin wedge-shaped ends which may be pushed well
under the bark without noticeably separating it from the growing layer. The
entrance points for scions are provided by extending cuts vertically for about
two inches from the wound at each point where a scion is to be inserted. The cut
bark at the upper end of the wound should then be raised i,lightly and one end of
the prepared , scion slipped into place. The other end of the scion is then inserted
in similar fashion into the cut bark at the lower end of the wound. For most
satisfactory results, the scions should be approximately in line with the grain
of the wood and of sufficient length to arch somewhat over the bridged area.
Small brads will hold the ends of scions in correct position, and liquid wax freely
applied to the upper and lower wound edges and to the edges of the attached scions
will prevent drying out. The number of scions required will depend upon the
size of the area to be bridged.

Disposal of Stumps. Two general methods for the disposal of tree stumps may
be employed. The stump may be removed entire from its site by aid of root
pruning and the use of heavy apparatus, or the stump may be destroyed in place
by burning or other means. If the former method is used, there may be certain
advantages to retaining a portion of the butt for purposes of leverage. Details
of this method are omitted here, however, since the use of heavy apparatus re-
quires the services of experienced operators.

The destruction of a stump in its site, when it cannot be readily disposed of
otherwise, may be accomplished in a reasonably simple manner after completing
certain necessary preparations. The part of the sti mp above ground should be
reduced as much as possible by cutting off the trunlc as near to the ground line
as convenient. Generally, in the case of a storm-uprooted tree, this operation
will be most satisfactorily completed by working on the tree without attempting
to free it from any position in which it may have become securely fixed. Upright
stumps may present some difficulty, while in the case of uprooted trees the dis-
posal is already partly accomplished. Having eliminated much of the stump
above ground, the next step is to reduce the underground stump. Removal of
the soil so as to form a circular trench, followed by progressive digging toward the
ball of the root, may consume time, but careful attention to this detail is essential
for later satisfactory progress.



TREE PROTECTION 29

Attention should next be given to the matter of severing any remaining roots
holding the stump in place. At this point the stump without root attachments
should be in such relationship with the ground that except for its weight it could
be readily removed from the hole. The closely packed soil about the roots, may
be removed with a pickaxe or washed off with a strong stream of water when
this facility is available. The use of water, even if dependence has to be placed
upon a heavy rainstorm, has advantages, particularly if local conditions permit
good drainage.

The root ball, free from soil, should then be allowed to dry thoroughly and any
parts of it which can be chopped off should be eliminated. In this way the stump
remaining for ultimate destruction can be still further reduced, and any axe blows
which fail to sever parts of the root stump completely enough for removal will
not be in vain since they will aid in the final destructive process.

The appearance and condition of the stump at this stage in the operations
should determine whether additional openings in the form of holes bored with an
auger are necessary before the application of kerosene. Intermittent applications
of kerosene daily allowing time for adequate penetration through entrances cut
and bored near the top of and throughout the stump, should be as numerous as
the varying tonditions may require. When penetration with kerosem is reasonably
complete, dry rubbish, placed over and about the stump, should be ignited. The
stump will then be either partially or completely consumed, depending upon the
thoroughness of preparation.

This method of destroying stumps may be curtailed or elaborated according
to the results desired. Sometimes the only objective may be the reduction of
size to permit burial of the stump in its original site. In other cases complete
destruction or reduction of the stump to a size which will permit easy removal is
necessary. It is obvious that this discussion is concerned principally with the
destruction of individual stumps in small-scale operations by a reasonably safe
method. Large-scale operations may employ temporary chimney construction,
forced draft burners, or explosives. The method outlined is of use primarily to
persons without expensive equipment or knowledge of machinery and construc-
tion. The chief penalties are the time consumed and the extra work necet^ary
in preparation.

Detecting and Reporting Defects. During the summer season, dead, defoliated,
and injured trees are often easily spotted by the absence, sparseness, or discolor-
ation of leaves. At other seasons signs of injury are less conspicuous, but frac-
tured limbs and some other injuries may be more clearly seen because of the
absence of foliage. The weight of snow and ice on branches sometimes causes
injury to trees, and prompt treatment or removal of injured parts should prevent
tree injuries from becoming injuries to persons or property.

The extent of damage to utilities' wires and other property resulting from fall-
ing trees indicates the need for detecting badly weakened trees before they
collapse. It may be pointed out that there is need for all utilities to keep their
lines under inspection and arrange for the immediate removal of any hazards
which threaten them. Intelligent cooperation by the public in reporting to their
municipal tree departments all dangerous trees, will aid in preventing service
failures and destruction of scarce materials.



30 MASS. EXPERIMENT STATION BULLETIN 397

CONCLUSION

Safe Trees the Minimiivi Requirement. In former years ffderal funds for
public works supplemented local appropriations and permitted many com-
munities to give needed care to municipally owned trees. More recently, war
activities have absorbed the personnel previously employed in this work to such
an extent that even when additional appropriations for tree work are available,
it is not always possible to have the work completed. In spite of obstacles, how-
ever, safe trees must be the minimum requirement for municipal tree piograms.

Responsibility and Organization. Unless some wa}' can be found to distribute
more adequately the responsibility for tree work, the number of trees neglected
over one or two years may increase to a point where no amount of community
organization can solve the problem. Already an increase in wire interference by
trees has been reported by the public utilities. It is essential that civilian and



Online LibraryMassachusetts Agricultural Experiment StationBulletin - Massachusetts Agricultural Experiment Station (Volume no.379-398) → online text (page 67 of 77)