Essentials of good pruning techniques - 2010

Essentials of good pruning techniques. By: Dr. Abdul Sattar Salih Al Mashhadani
Parks Recreation Facilities (PRFD), Infrastructure & Municipal Assets Sector, Municipality of Abu Dhabi City.
June 2010
Infrastructure & Municipal Assets Sector
Parks Recreation Facilities (PRFD)
Essentials of good pruning techniques
‫اﻟﺠﻴﺪ‬ ‫اﻟﺘﻘﻠﻴﻢ‬ ‫ﺗﻘﻨﻴﺎت‬ ‫أﺳﺎﺳﻴﺎت‬

Some Professional Terms
Bark – outer layer of stems and trunks; protective tissue.
Branch – stem originating from another, larger stem.
Branch bark ridge – protruding bark at the top of the junction (crotch) of
two branches; continues downward from crotch.
Branch collar – junction (overlap) of tissues of two branches or branch and
trunk.
Bud – small dormant apical or lateral meristem; may be foliar or floral
tissue; undeveloped flower or stem.
Canopy – branch and leaf portion of tree (also called ‘crown’).
Cavity – open wound or hollow in trunk of tree; result of decay.
Central leader – main growing terminal stem of a tree.
Co-dominant stems – two equally competing terminal branches.
Crotch – top of the union of two branches or of branch and trunk.
Crown – aboveground portion of tree.
Crown cleaning – removal of water sprouts, suckers, dead, dying,
diseased, deformed and damaged branches.
Crown reduction – alternative to topping; reducing canopy by appropriate
pruning techniques.
Crown restoration – technique to restore growth habit of topped or
damaged tree. Decay – deterioration of woody tissue by diseases and due
to bad maintenance.
Dieback – condition of death of many terminal branches.
Dormant – at rest, or in a state of reduced activity.
Drop cut – second cut in 3-cut process of removing a branch.
Drop zone – area where cut branches may fall during pruning.
Evergreen – trees that keep their leaves or needles year-round.
Flush cut – improper pruning technique; removes branch collar and
damages trunk.
Heading back – pruning shoots back one-half to one-third to buds or twigs
with potential for growth.
Heartwood – inner wood (nonfunctioning xylem) that gives strength to the
trunk.

Some Professional Terms
Included bark – bark tissue lodged in the crotch of two branches or branch and trunk
indicating weak attachment.
Lateral bud – vegetative bud on side of a branch.
Leader – primary terminal stem of a tree .
Lowest permanent branch – lowest limb that will remain in tree canopy.
Main branches – those that make up the canopy of the tree (scaffold branches).
Mature height – tallest expected growth of a tree.
Mature tree – has reached approximately 75% of its full canopy growth.
Multiple leaders – co-dominant stems competing for central growth of tree.
Natural target pruning – technique of removing branch that protects the branch collar;
3-cut process.
Permanent branch – branch that will remain on tree; initial scaffold framework.
Pollarding – specific pruning technique for height
Lateral – side branch or smaller twig of a limb. restriction of trees.
Pruning – cutting away undesirable parts of a tree.
Raising – removing lower branches to provide clearance.
Reduction – pruning to reduce height and/or spread of canopy.
Respiration – cellular process releasing energy from stored foods.
Restoration – pruning to recover shape and strength of damaged canopies.
Scaffold limb – permanent, main branch of the canopy. Abundant vertical and radial
spacing improves tree structure.
Site considerations – factors to take into account when determining what trees to
select for the location.
Structural pruning – pruning to develop a sound scaffold branch system in a tree.
Sucker – shoot originating from a root or lower trunk.
Temporary branches – shoots that remain during training of young trees, to be
removed as tree matures.
Terminal bud – bud at the apex of a stem.
Tree- woody vegetation 5 cm or greater in diameter to be measured at ground level.
Tree protection zone – area of tree roots to be designated by fencing to prohibit
access during construction activities. Minimum 2.4 m radius, or usually 30 cm radius
per 2.5 cm diameter at breast height.
Thinning – selective pruning of entire stems to increase air or light penetration to
canopy or to decrease branch weight.
Trunk – base stem of tree that supports canopy.
Undercut – first of 3-cut process in natural target pruning. Prevents bark tearing.

Branches
Branches are attached to the tree trunk by
interlocking branch and trunk tissue. A new
layer of interlocking tissue is produced
each year over the previous layers. A woody
branch collar, produced by the trunk, holds
the branch base. When branches on the main
trunk that have a narrow angle increase in
Diameter they eventually run out of room to
grow. The branch bark becomes surrounded
by woody trunk and branch tissue. The bark
that becomes overgrown is referred to as
included bark (Figure). The union is weak and
likely to split.
V - shaped crotches can lead to included bark

The branch collar is the swollen area of
trunk tissue that forms around the base
of a branch.
The branch bark ridge is a line of rough
bark running from the branch-trunk
crotch into the trunk bark, less
distinguished on some trees than on
others

WHAT IS PRUNING?
Pruning is a regular part of plant maintenance
involving the selective removal of specific plant parts.
Although shoots and branches are the main targets for
removal, roots, flower buds, fruits and seed pods may
also be pruned.
Pruning wounds plants, but plants respond differently
to wounding than do animals. In plants, damaged
areas are covered by callus tissue to close wounds.
Another response to pruning occurs inside plants.
Chemical boundaries form around wounded areas,
walling off the wounds. Compartmentalization limits any
decay that results from wounding.
Use proper pruning techniques that minimize plant
wounding and speed wound closure.

Common Pruning Mistakes
Flush Cut
Flush cuts cause underlying tissues to dry
out slowing callous formation, are subject
to insect invasion and promote tissue
die-back.

Stub Pruning
Pruning cuts that leave a branch stump can
result in tissue die-back (A) or reproduction
of unwanted branches (B). Stumps may also be
a hazard to pedestrians by snagging clothing or
causing injury to passersby.

Common Mistakes

What is "topping"?
Topping occurs when the vertical stem (leader) and upper
primary limbs (scaffold branches) on mature trees are cut
back to stubs at uniform height.
Topping is also referred to as heading, stubbing, or
dehorning.
How does topping damage trees?
1) Topping reduces food-making capacity. Trees require a
large leaf surface area to provide food for maintenance and
growth. Topping cuts off a major portion of the tree's food
making potential and depletes the tree's stored reserves.
2) Topping stimulates undesirable "water sprout" growth.
While removing most of the buds that would form a normal
branch system, topping often stimulates the regrowth of
dense, unattractive, upright branches (water sprouts) just
below the pruning cut. Water sprout regrowth is vigorous. A
topped tree will rapidly return to its original height, but will
lack its original form.
Common Mistakes
TOPPING

What is "topping"?
3) Topping leaves large wounds. The branch wounds left from
topping are slow to close, therefore more vulnerable to insect
attacks and fungal decay. An invasion by either pest can
spread into the trunk, killing the tree.
4) Topping creates a hazard. Weakened stubs are more prone
to wind and storm breakage because they generally begin to
die back or decay.
5) Topping injures bark. Increased sun exposure on trunk and
branches can lead to severe bark damage.
6) Topping disfigures trees. Ugly branch stubs, conspicuous
pruning cuts, and a broom-like branch growth replace natural
beauty and form. Topping reduces the real estate value of
trees by 20 - 100 percent. A correctly trimmed tree increases
in value at each pruning

Why are trees topped?
Some unprofessional tree pruners practice topping
whenever trees reach an undesirable height.
They mistakenly believe that topping will reduce the storm
hazard of falling branches, when in fact, topping has the
opposite effect.
People also top trees when they interfere with utility wires,
buildings, solar collectors, or sunny garden areas.
Can topping be corrected ?
A professional arborist can improve the condition of a
tree, even after it's been severely topped and shows heavy
water sprout regrowth. As the water sprouts begin to gain
caliper, they can be selectively "thinned out" using
properly placed branch collar cuts. New growth can be
directed outward to expand and round out the crown.
This process will need repeating for a few years. The
scars, both physical and visual, will never completely
disappear.
Topping is only appropriate when
sections of limbs are cut off during the
removal of a tree.

What are the alternatives ?
A wiser alternative to topping is careful selection and
training of the young trees. Avoid topping altogether.
Allow your trees to realize their full potential for health and
beauty in the landscape.
In order to avoid topping we have to consider :
Selection of trees that only reach desired maximum
heights eliminates severe pruning later.
Newly planted trees should be properly pruned to
develop a good branch structure as they grow.
When a mature tree's height must be reduced, an
alternative to topping is drop-crotching.
The tree must prune heavily every five to seven years.
If the tree is too large for the site, replace it with a smaller
species ( last option).
Alternatives

Why Should Trees Be Pruned?
Pruning should be done
properly with an
understanding of how the
tree responds to each cut as
well as which branches need
to be removed
Pruning is the most common tree maintenance procedure.
Trees that grow in the forest grow quite well with only
natures pruning. This is due to their richness in soil and
other natural conditions.
Landscape trees require a higher level of care and proper
pruning to:
improve their structural strength,
maintain their safety
maintain their health,
enhance their beauty,
increase their value.

• Pruning is advisable if:
trees have crossing branches, weak crotches,
or other defects
branches are dead, dying, decayed, or
hazardous
lower branches interfere with people or
vehicles, or block visibility of signs
branches are growing into buildings or utility
wires
limbs have been broken by storms
trees have grown too large and might injure
people or damage property
• Landscape trees not only make homes and
communities more beautiful,but they also
improve our environment and can increase
the value of a property up to 20 percent.
• Trees are truly assets that need to be
enhanced and protected. Proper pruning is
definitely a worthwhile investment!

Who is Qualified to Prune Trees?
• Simple types of pruning, such as cutting lower
branches from small trees, can be done by
anyone who understands plants and has the
proper tools.
• Only qualified arborists should train young trees
or climb into larger trees to prune them.
This type of tree work requires knowledge of
scientifically based pruning techniques, tree
physiology, and safety practices, as well as
working experience with various tools and tree
species. Because proper pruning is complicated and
examples of shoddy and unsafe work abound.
Any potentially hazardous activity associated with
climbing trees, using power tools, and especially
working near electric lines should be left to qualified
professionals who know how to follow the tree
safety means.

Types of Pruning Cuts
When using thinning cuts, always remove or
shorten a branch to a side branch that is at least
one-third the size of the one being cut. A branch that
is 7.5 cm in diameter would be pruned back to a side
branch that is at least 2.5 cm in diameter. Do not
remove more than 25 % of a mature tree’s foliage in
any year.
1)Thinning cut : removes a branch at its point of origin
on the trunk, or shortens a limb to a lateral branch large
enough to resume the growth of the pruned limb.
Thinning cuts leave no stubs. They are used to remove
damaged, dead, or weak branches, reduce the length
and weight of heavy limbs, or reduce the height of a
tree.
Thinning cuts are placed so as to distribute ensuing
growth throughout a tree and retain or enhance a
tree’s natural shape.

2) A heading cut trims a branch back to a bud, or trims a
branch or leader back to a small branch not large enough to
simulate the growth of the pruned branch.
Heading cuts are only appropriate for specific reasons that
apply to some species.
Heading cuts should only be used when pollarding
trees or shaping terminal flowering plants such as
roses
they should not be used for topping trees. Topping has
been described as the “ultimate in destructive
practices,” and in almost all cases it permanently
damages a tree’s health, structure, and appearance
• 3) A stub cut is like a heading
cut but is made indiscriminately
to a point on a branch or leader
where no bud or branch exists.
It, like a heading cut, is used
when a tree is topped.

Thinning a tree removes unwanted
branches, reduces weight, and allows
light and air penetration
Tree Care Professional
It is very difficult, if not impossible, to repair damage
that has been done by poor pruning.
In tree work, the old proverb
“you get what you pay for” is usually true
Proper pruning Indicators :
use of thinning cuts, rather than topping, heading, or
stub cuts, so that the natural form and branching habit
of the species is preserved
cuts placed just outside the branch collar, not flush cuts
absence of torn bark where branches have been cut.

Training Young Trees
For pruning a young tree, it is important to
consider :
It’s natural form
desired future growth of the tree
A few minutes of thoughtful pruning spent can
eliminate hours of costly future maintenance
and corrective pruning on mature trees
Ideally, pruning should be done over several
years to train a young tree.
Prune as little as possible in the first two years
after a tree has been planted, so there will be
enough temporary branches and leaves to
produce food for the growth of roots, trunk, and
branches.
Newly planted trees will gradually restore the
balance between roots and branches; excessive
pruning can be detrimental and delay the return
to normal growth.

Training Young Trees
When a tree is planted, prune only broken,
malformed, or diseased branches.
Remove any double leader so that one dominant
trunk is maintained.
Removing branches before they exceed 2 .5 cm
in diameter will keep pruning wounds small.
Street trees or trees along walkways and
driveways must have limbs high enough to
safely accommodate pedestrians and vehicular
traffic, signs, and lights ( 1.8 m ) .

To promote good structure and lessen the need for future pruning, branches that
should be properly pruned from newly planted trees during the first one to five years

Pruning Mature Trees
Not all mature trees need to be pruned. Some only require pruning every
5 to 10 years.
The need for pruning can be reduced by planting the right species
of tree in the proper place and by properly
pruning a tree when it is young
Mature trees should only be pruned for specific purposes and in a
manner that protects and preserves the tree’s natural form.
Pruning should focus on maintaining
tree structure, shape, health, and safety.
Types of recommended pruning :
Crown cleaning—removes dead, dying, diseased, crowded, weakly
attached, or low-vigor branches and water sprouts.
Crown thinning—selectively removes branches to increase light
penetration and air movement and reduce the weight of heavy limbs.
Crown raising—removes lower branches to provide clearance for
buildings, vehicles, pedestrians, and signs.

Crown reduction— reduces the size and spread of crowns
using thinning cuts, resulting in fewer sprouts than heading or
stub cuts, and maintaining
the structural integrity and natural form of the tree (Fig).
Crown restoration—improves the structure and appearance of
trees that have been storm-damaged or deformed by heading
or stub cuts.
Vista pruning—thins selectively to open a specific view of an
object or scenery.

The ideal mature tree will have lateral branches that are 45- 60
cm apart on the trunk and one strong leader. However, some
trees differ, such as many ornamentals, which are meant to
have a more bushy appearance.
The preferred method for reducing the size of a crown is the
use of small thinning cuts.
Using larger thinning cuts that remove a large branch or
leader to a large branch is commonly called crotching or
drop-crotching.
Even though large wounds may result from drop-crotching,
this method of pruning is preferable to heading or stub cuts.

Drop crotching
Drop-crotching is a type of thinning cut that reduces a tree's
size while preserving its natural shape.
To drop-crotch,
select and cut higher branches back to laterals at least one-
third the diameter of the limbs being removed.
Cut outside the branch collar at a 45 to 60 degree angle to
the branch bark ridge.
Leave the branch collar undamaged to help prevent decay
from entering the trunk.
This type of thinning cut will stimulate growth throughout the
tree and discourage water sprout development.
Lateral limbs are pruned where they join large diameter side
branches.
The center leader is cut back to a large diameter secondary
branch so that a modified leader remains.
This does not change the direction of growth. It
encourages stimulation of the apical growth point.

Drop-crotching

dominant leaders-Correct cut for co

Correct cut for co-dominant leaders

Proper pruning
A tree branch has a branch bark ridge, often referred to as
a branch collar, that separates the branch from the tree
trunk (Figure). The collar is the swelling located at the
base of a branch where the branch meets the trunk. The
callus that forms the collar is an area of tissue that
contains a chemically protective zone. The natural
decay of a dead branch stops when it reaches the collar.
When pruning a dead branch, do not create a new wound
by cutting into the ring that forms around the dead branch.
The angle A created be the branch bark ridge and an Imaginary
line with the tree trunk is the approximate angle B at which to
make the pruning cut

Whenever removing limbs greater than 2.5 cm in diameter, use
the three-cut method to avoid tearing bark.
1)First, about 30 cm from the trunk, cut halfway through
the limb from the underside.
2)Second, about 2.5 cm past the first cut, cut through the
limb from the top side. The limb's weight will cause it to
break between the two cuts.
3)Make the third cut outside the branch collar, as
described earlier. Use a handsaw to provide greater
control.
Don't coat pruning cuts with tree paint or wound
dressing, except for control of certain disease-
carrying insects. These materials won't prevent
decay or promote wound closure
Three-cut Method

Proper pruning

Properly pruning young trees means lowering
future maintenance costs and creating
a beautiful and safe mature trees.
Proper pruning

Pruning cut angles dictate the pattern
of wound tissue formation
Improper pruning cut angles result in
incomplete distribution of wound healing tissue
that will slow the healing process and can lead
to die-back, infestation by insects or infection
by fungi and bacteria.

Proper Pruning and Healing
Correct cut results with
good wound wood pattern
Cuts that preserve the branch collar form a complete
ring of callus tissue, heal rapidly, help prevent
invasion by pests and ultimately promote healthy
growth.

Pruning Cut Angle and Placement
If the cut is …..
too steep (A) the tissue can dry before
healing and cause die back.
too flat an angle (B) leaves a blunt
surface that can collect dust & water
which slow wound healing and can
promote decay.
too far (C) from a lateral branch or bud
can over stimulate new growth resulting
in undesirable multiple, tightly packed
branches, die-back and defeat the original
purpose of pruning.
Make pruning cut directly above a
bud or lateral branch at about a 45
degree angle. Such cuts result in
controlled growth of the cut branch
and healing of the pruning wound.

Sharp blades leave smooth cuts

• Finally, we advise that, from today, all
pruners are required to practice the
remedial pruning of woody plants by
implementing the Five D's (prune these
branches at any time) :
• Dead branches
• Dying branches
• Damaged branches
• Diseased branches
• Deformed branches
In almost all cases, thinning cuts are
the proper type of cut to use in tree pruning

Recommendation
we need to prepare and develop our national
standards for the best methods and tree safety
means.

References
• Al Mashhadani Lectures.
• Al Mashhadani A. S.(2001). "Pruning & its rules and hazards".Al-Asimma Mg. No.64-
2001, Abu Dhabi, Municipality, UAE.
• Klingeman,B. et al.(2008). Best Management Practices for Pruning Landscape
Trees, Shrubs and Ground Covers, University of Tennessee, USA.
(http://www.utextension.utk.edu/publications/pbfiles/pb1619.pdf)
• Shigo. A. L, (1998), Modern Arboriculture, third printing (2003), Sherwin Dodge
Printers, USA.
Data base
• http://forestry.about.com/od/arboriculture/ss/why_prune_7.htm
• http://forestry.about.com/od/treeandforestcare/ss/sucker_sprout.htm
• http://home.howstuffworks.com/how-to-plant-trees-shrubs-and-vines7.htm
• http://if-srvv-edis.ifas.ufl.edu/document%20mg087
• http://web1.msue.msu.edu/msue/imp/modzz/00001781.html
• http://www.afmanconsulting.com/articles/pollarding.html
• http://www.bakker.co.uk/G_515/Pruning-tools-for-trees-hedges-and-shrubs.htm
• http://www.derby.gov.uk/LeisureCulture/ParksRecreation/Treepruningtechniques.htm
• http://www.extension.umn.edu/distribution/horticulture/dg0628.html
• http://www.gotreecare.com/shrubpruning/pruningequipment.html
• http://www.passionfortrees.co.uk/html/pollard.html
• http://www.treedictionary.com/DICT2003/tree_pruning/history/history-1.html
• http://www.treedictionary.com/DICT2003/tree_pruning/pollarding/starting.html
• http://www.treesaregood.com/treecare/pruning_mature.aspx
• http://www.treesaregood.com/treecare/topping.aspx

Essentials of good pruning techniques - 2010

Recommandé

Recommandé

Contenu connexe

En vedette

En vedette (7)

Similaire à Essentials of good pruning techniques - 2010

Similaire à Essentials of good pruning techniques - 2010 (20)

Plus de Abdul-Sattar Al-Mashhadani

Plus de Abdul-Sattar Al-Mashhadani (20)

Essentials of good pruning techniques - 2010