Massachusetts Agricultural Experiment Station.

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

. (page 66 of 77)
Online LibraryMassachusetts Agricultural Experiment StationBulletin - Massachusetts Agricultural Experiment Station (Volume no.379-398) → online text (page 66 of 77)
Font size
QR-code for this ebook

soil, which often prove a source of trouble later. Careful planting in a well-
chosen site is the best insurance for the future growth of the tree. Sometimes
after an area has been planted, new buildings or other factors may necessitate
the removal or transplanting of the trees. Turf grading operations which fail to
piovidc a needed brick- or rock-lined wall around trees are a common .'•ource of
trouble. The installation of curbing, hard-surfaced roads, and sidewalks may
result in root injury. Erosion of soil during these operations and under a variety
of other conditions may dangerously undermine trees. Weakening of anchorage
should be guarded against in all locations.

Narrow Tree Belts. In most communities, public shade trees are ordinarily
planted in the space between the hard surface road and the sidewalk. In some
instances this area is extremely narrow, but widening is often precluded by exist-
ing conditions. Trees restricted in this way are under a severe handicap and in
most cases have been observed to do better than one would reasonably expect.
Extended periods of drought or other tests of vigor, however, sometimes take a
heavy toll of weak trees in narrow planting belts.

Storm Damage. Ice storms, lightning, high winds, hail, hea\'>- rain, and snow-
result annually in severe damage, and btorm injuries accumulated o\er any
extended period of time may result m trees becoming serious hazards in the
community. Injury initiated by the hurr'cane of 1938 has served as a basis for
subsequent extensive damage and, in some cases, ultimate death of trees.

Girdling Roots. In planting a tree, if care is not taken to provide a hole of
adequate size in which to spread the roots, there is danger that they may become
wrapped around the trunk in such a manner as to choke the normal growth (Fig.
4). The ill-advibed application of a fertilizer close to the base of trees may cause
excessive root development and girdling about the trunks. Girdling roots are
not necessarily harmful, particularly if root grafting results. When a girdling
root above or below ground is detected as the cause for tree weakening, it ma}' be
severed and the constriction of the trunk somewhat relieved.

^ McKenzie, M. A. and L. H. Jones. Injury to trees from sulphur dioxide fumes of electric
refrigerators. Science 91:239-240. 1940.


Other Girdling. Wire guards, fences, and supports in contact with trees may
girdle the trunks and cause permanent scars, injury, or death.

Injury by Animals. In former days the gnawing of the bark of street trees
by horses was often cited as a source of injury and possibly wounds caused in
this way may again become common. At present, however, damage by horses
is not a serious problem although limited injury to tiees may be caused directly
or indirectly by some other animals.

Frost Cracks. A sudden drop in temperature may result in the withdrawal of
water from the cells of the wood in a tree trunk and its fixation as ice crystals.
The resulting cell shrinkage lacks uniformity and creates a tension within the
woody tissue. With the development of sufficient stress, rending occurs along
the grain of the wood. An accompanying loud report may be the first warning
of this type of injury. The sharp lengthwise clefts commonly seen on the south
and southwest exposures of trees are the ultimate wounds of this sequence. Frost
ridges in which splitting of the wood results without rupturing the bark differ
only in the degree to which the shrinkage of woody tissue takes place or sufficient
tension develops. Many frost cracks close and heal readily (Fig. 5, A) when the
shrunken tissues thaw and absorb a sufficient amount of water. Sometimes,
however, a frost crack may become a permanent weak spot (Fig. 6) which will
reopen each winter and may be effectively closed only by mechanical aid, such
as screw rods inserted through the tree trunk at right angles to the fissure.

Slime-flux. Wet yellowish streaks e.xtending down the limbs and trunks of
trees are frequently observed to originate at an injured crotch (Fig. 6), the cut
at which a branch has been severed, or in some other wound. A slimy ooze in
which fermentation organisms become active may continue to flow down the
surface of the bark for a considerable period of time and in persistent cases where
the bark and growing tissue are continually wet, extensive injury may result.

Lost Protection. Some trees requ're protection from drying winds or excessive
heat or cold. Since the hurricane of 1938 in which such protection was sometimes
lost, resultant injury has been particularly conspicuous. Tree owners reasoned
that sheltered trees survived the hurricane, but failed to evaluate critically the
post hurricane exposure of these trees resulting from lost protection.

Branch Wounds. Friction resulting from the rubbing of branches or the con-
tact of public utility wires with branches often causes wounds which may later
directly or indirectly result in the death of certain parts of trees. Utility compan-
ies have long since learned that where wires are in direct contact with trees there
is not only the immediate prospect of interrupted service from burning as a result
of contact of the energized wire and grounded tree, but also the later penalty of
the killed branch crashing through the wires.

Trunk Woimds. It is not uncommon to find the trunks of trees debarked by
automobiles, snowplows, or lawnmowers. Such injuries may be the beginning
of serious trouble, serving as points of entrance for decay organisms and the
ultimate weakening and collapse of trees.

Unusual instances of trunk wounding, as those associated with the Connecticut
Valley flood of 1936, are sometimes difificult to explain after the conditions caus-
ing them no longer prevail. For example, trees situated In locations which now
appear to be at a safe distance from flooding waters show bark injury known to
have been caused bv ice floes.


Root Injuries. The most conspicuous root injuries are those resulting from
excessive root pruning; especially the type shown in figure 7, upper. The almost
certain sequel to such pruning is shown in figure 7, lower.

Neglected Pruning. Most trees require a minimum of pruning for health,
appearance, disease control, safety, utility line clearance, or other considerations.
Delay in pruning or failure to prune correctly may prove to be a costly mistake,
especially in municipal shade tree management. Severe damage to neglected
trees, injury to citizens or their property, as well as the interruption of the service
of wire-using agencies, may result.

Branch Stubs. Careless pruning or storm injuries sometimes leave jagged
branch stubs as an invitation to wood-destroying fungi. Probably tree deteriora-
tion starts in this way more often than in any other.

Exposed Wounds and Cuts. Many tree casualties are found to result from un-
treated wounds and cuts. Prompt treatment of wound: and immediate attention
to cut surfaces following the removal of branches are constructive preventives
useful in checking early deterioration.

Cavities. Extensive cavities in trees represent the advanced stages of pro-
gressive decay following injuries. The best treatment for them is to prevent their
occurrence, or check their progress.

Dangerous Trees. Trees seriously weakened by disease or decay at a large
crotch (Fig. 2), and skeleton trees which have ceased to serve communities for
purposes of shade not only are frequently a blot on the landscape but may actually
constitute a serious menace. Sometimes failure to appreciate the need for the
prompt removal of such trees or the lack of responsibility for this work may cause
serious delay in the removal of a dangerous tree. The result of this delay may
prove injurious, fatal, or costly to someone.

Evergreen Failures. Coniferous evergreens may be injured by the weight of
snow on branches or tree tops. When parts of trees are broken, the same treat-
ment accorded wounds of deciduous trees may be given or may be altered as
necessary. In all cases, branch stubs or rough jagged edges of wounds should be
cut back smoothly. The resin coating which usually covers cut surface b of
evergreens suffices as a dressing. When trees are broken during a wind or wind-
and-rain storm, the entire tree or most of it commonly falls (Fig. 1). The guj -
ing of evergreens in certain locations will sometimes prevent accidents of this

Trees and Utility Wires. Trees and wires both serve society in war as in
peace. Adequate tree maintenance and maximum service from wire-using agen-
cies ,do not represent fundamentally divergent policies. Certain conflicts between
trees and wires are inevitable, however, and the results of some of these conflict?
and the mechanical devices adapted to overcome or minimize them are shown in
figure 8. Shade tree maintenance has benefited materially from the joint use
of poles by uulities, as well as in other progressive utility programs. The almost
forgotten overhead w're mazes (Fig. 9) which have been compacted (Fig. 10)
and in many cases placed underground, foretell even better conditions for ."^hade
trees in the future. Placing utility wires underground, however, should not be
considered a panacea. In certain instances this practice is desirable and practical,
but at other times the cost to consumers would be prohibitive. Nor should it be


supposed that wires underground may be forgotten, since tree roots and wires
may sometimes conflict. For the present, however, the equipment of wire-using
agencies is not likely to be changed materially, and there should be opportunity
for additional study of problems concerned with overhead wires and trees.
During wartime, extra vigilance is necessary to insure the fullest measure of un-
interrupted service from both trees and wires, and accidents resulting from the
falling of weakened trees should be prevented.

The following data prepared independently by L. B. Shepherd, Division Toll
Service Supervisor, New England Telephone and Telegraph Company, indicate
the nature of tree troubles encountered by wire-using agencies. A total of 35
percent of toll open wire troubles is associated with trees, principally sugar
maple, poplar, elm, birch, spruce, beech, and oak.

Sugar Maple — Failure occurs at the crotch, and at the time the limb is in leaf.
To all appearances, the tree may be a healthy one. It is suggested that crotches
of old maples be checked for decay, and that ends of limbs be examined for indi-
cations of dj'ing branches.

Poplar — Failure occurs by trunk breaking off either at base or near top of
tree, after tree has reached 8 to 10 inches in diameter.

Elm — Failure occurs in large elms at the crotch or midway in limb, probably
on account of the resistance to the wind when the tree is in full leaf. Crotches
should be checked as suggested under "Sugar Maple", and crotch reinforcementb
should be provided for those limbs considered hazardous. Experience has shown
that limbs of elms are brittle, and snap easily under pressure.

Birch (White or Yellow) — Failure occurs during period of hea\y wet snow.
Trees become laden with snow and ice and lie over into wires.

Spruce or Pine — Failure occurs during violent wind, and trunk snaps ofif about
15 or 20 feet from ground line. It is suggested that attention be given to trees
that are leaning (probably result of hurricane), shallow rooted, and have dying

Beech and Oak — Failure occurs when trees are leaning into wires, particularly
on sidehills.

Cutting Wood for Home Use. The fuel shortage has brought an increase in
the number of inexperienced persons chopping wood for home consumption.
In order to accomplish the most for their efforts, persons will do well to consult
their county agricultural agents and inform themselves on time-saving methodf
in the cutting and use of fuelwood. Careless chopping has in some instances
resulted in serious damage to utility service. Fuel conservation of this type is
indeed attained at a high cost in other critical materials and service. The felling
of trees on wires should always be avoided, and in doubtful cases, chopping in the
vicinity of wires should not be attempted. Extended luelwood programs organ-
ized to save other types of fuel serve a valuable need if dangers of spreading the
Dutch elm disease and damaging service of wire-using agencie.- are carefully
guarded against. With certain limitations on the disposition of elm wood, as
indicated elsewhere in this publication, the consumption of wood from hazardous
trees may be an important supplement to the fuel conservation program, espec-
ially in cities where woodlots are not often immediately available. How-
ever, attention should be called to the fact that trees in the public way or on the
boundaries thereof are the responsibility of the tree warden, and promiscuous
cutting by individuals is unlawful. Disposition of the wood after a tree is cut
may be arranged by the municipal officer in charge of trees.


Harmful Practices. Willful maltreatment, panacea claims, and tree magic
are for the most part of historical interest only in connection with modern tree
care. An informed public, the sincere efforts of the members of the arboricultural
profession, and in some states the licensing of tree workers, have done much to
establish the scientific treatment of tree troubles. Damage sometimes results
from carelessness, inadequate diagnosis of tree defects, or the employment of
inexperienced operators, and every effort should be made to shun these pitfalls.


Essential Considerations. Many of the operations essential to the satisfactory
maintenance of shade trees can be completed by persons without specialized
training. Nevertheless, certain important considerations concerning trees and
apparatus and materials employed should always be borne in mind.

A person contemplating tree work would do well to inform himself concerning
the nature of the tree, details of the operat'ons involved in his. plans, and the
equipment and materials necessary for the work. By so doing he will more full}'
appreciate the significance of the completed job whether he does the work him-
self or employs others to do It. An excellent procedure before beginning actual
operations on a tree is to make a diagram to scale showing the operations con-
templated. In this way an individual will give himself the opportunity of ex-
periencing practical problems involved and develop an intelligent plan of action.
Whenever possible, attention should be directed toward corrective treatment of
minor defects and the prevention of major injuries by early treatment.

Poisonous Materials. Many of the materials uced for the protection of tree
wounds and as sprays on foliage are poisonous, inflammable, or caustic. Utmost
care in handling all materials should be exercised constantly, therefore, and all
materials should be used only in accordance with direct'ons furn'shed by the
manufacturer. One should always be mindful of protecting other persons,
animals, and property from damage resulting from operations or the use of mate-
rials. Unused materials likewise require attention and should not be stored in
places, or under conditions, in which they are or may become hazardous.

Poisonous Plants. Two important woody plants associated with injury to
humans are poison ivy (Rhus toxicodendron L.) and poison sumac {Rhus vernix L)
(Fig. 11), and all persons working with trees would do well to be able to recognize
both of these plants in the field. Detailed descriptions and discussions of poison-
ous properties are available elsewhere for those interested; attention here is
directed to the need for avoiding direct contact with roots, stems, leaves, flowers,
or fruits — as well as the smoke arising from the burning of any of these plant
parts. Injury to humans is an irritating dermatitis, the extent of which varies
greatly according to the individual. Specific directions are required for any
effective program dealing with ivy and sumac eradication.

Electric Current. For reasons of personal safety, as well as the protection of
utility service, work on trees or parts of trees in close proximity to wires should
be undertaken only by authorized persons, skilled in this particular practice.
Individuals observing the need for tree work of this type should make prompt
report to, or obtain information from, the tree warden or other duly designated
municipal officer.



Figure 1. A fallen evergreen tree with decayed trunk. Failure in this free blocked the high-
way and disrupted service by wire-using agencies. Inspection could probably have detected the
trunk weakness in the decayed tree. Note undisturbed sound evergreen in foreground which
was subjected to the same meteorological conditions. Photograph furnished by Boston Edison Co

Figure 2. Advanced decay in this elm and a sleet storm combined to interrupt wire service
in this community. Damage by this fallen tree could have been even more serious; note prox-
imity of dwelling house and police and fire equipment. Photograph furnished by Boston Edison Co.



Figure 3. The fungus, Polyporus versicolor Linnaeus ex Fries., fruiting on tiie trunk of a
maple. Abundant fruiting of this fungus, which grows on dead sapwood, is an indication of ex-
tensive weakness in a tree.



Figure 4. A red maple almost completely girdled at the base by a root. Note bulging of trunk
slightly above ground line, which is characteristic of this trouble. Root causing the girdling is
often slightly under the surface of the ground.



Figure 5. A. Frost crack which healed. Closing was complete, but cutting back of bark to
healthy tissue and sterilization and dressing of wound were necessary to promote satisfactory
wound healing.

B. A treated hurricane wound in which the bark was cut back to a smooth regular
contour and shellacked. Wound dressing was applied to wood. Complete healing of the wound
may be expected in such cases.



Figure 6. An elm in which a frost cracl< extended from a crotch down the trunk. Note repeated
•reopening and resultant slime-flux.



Figure 7. Tree anclioraj>e weakeneti by excessive tool pruning. Note cracking of soil shown
in upper photograph taken well in advance of casualty shown in lower photograph.




1 if

Figure 8. Tree trouble board prepared by wire-using agencies. Approximately x 1 9,
A. Electric light insulators used by liglit companies to protect wire from trees.
Telephone tree wire used for drop wire through trees.
Telephone wires showing abrasion from trees.

Effect of contact with light wire after insulation was worn off in tree.
Electric light tree wire before use.
Electric light tree wire showing abrasion from trees.
Electric light wire showing wear from hanging in electric light insulators.
Tree guard for telephone wire.

Tree guard for telephone cable covering cable and strand.
Tree guard for telephone cable covering strand only.












foli^rsome^pofes werl "oTeefS" with'^oVros'stmT'^T^^ ''?',*'^^" P'^'-^ '"-^^ Broadway
>vay and Maiden Lane. New York carried lloS Tod J ,',nr'^,i'"^ "^^"^ '^e corner of Broad-
there are about 30,000 telephone wirerin 17 r^hli^.tp^K"''^^ ''''* ^'''"^ s

Online LibraryMassachusetts Agricultural Experiment StationBulletin - Massachusetts Agricultural Experiment Station (Volume no.379-398) → online text (page 66 of 77)