Tree Pruning
Pruning:
Is selective removal of parts of a plant, parts such as branches buds or even roots.
Types of pruning and why we prune:
To remove deadwood, shape to control growth, improve or maintain health, reduce risk from falling branches, to prepare for transplanting, to increase the quantity of fruit in fruit bearing trees.
Different pruning techniques may be used on different trees and shrubs. Hedges for example are usually controlled with the use of a hedge trimmer rather than by pruning.
The tools of the trade for pruning are hand pruners, loppers, and chainsaws.
In general, the smaller the branch that is cut, the easier it is for a woody plant to compartmentalizethe wound and thus limit the potential for pathogen intrusion and decay. It is therefore preferable to make any necessary formative structural pruning cuts to young plants, when possible, rather than removing large, poorly placed branches from mature plants.
·
1 Pruning landscape and amenity
trees
1.1
Dead-wooding
1.2 Crown and canopy
thinning
1.3
Crown canopy lifting
o
1.4 Directional or formative
pruning
o
1.5
Vista pruning
o
1.6
Crown reduction
o
1.7
Pollarding
·
2
Types of pruning
·
3 Technique
o
3.1
Pruning to a bud
o
3.2 Pruning to a main
branch
o
3.3
Large heavy branches
·
4
Time period
·
5 See also
·
6
References
·
7
External links
[edit] Pruning
landscape and amenity trees
Pruning when there's a branch collar:- Note the swollen area where the branch joins the trunk, this is
known as the collar, do not cut off the collar
Pruning when there's a collarless union:- Note there's no swollen area where the branch joins the trunk, this
is known as a collarless union, cut at a mirror angle to the BBR (branch bark
ridge)
Pruning when it's a codominant stem:- Note the bottom of the BBR and where it meets the outside of the
stem, cut where the red line is.
Branch structure and how they are attached to
each other in trees falls into 3 categories. Collared unions, collarless unions
and codominant unions. Each specific attachment has its own unique way of being
cut so that the branch has less chance of regrowth from the cut area and best
chance of sealing over and compartmentalising decay. This means that there are 3
types of cuts made, whether that be to remove a little branch coming of another
or cutting a whole branch off back to the trunk. This term is often referred to
by arborists as
"target cutting".
Some of the terms used predominantly by
arborists and what they entail:
[edit]
Dead-wooding
Branches die off for a number of reasons ranging
from light deficiency, pests and disease damage to root damage. A dead branch
will at some point decay back to the parent stem causing abscission and fall
off. This is normally a slow process but can be shortened by high winds and
extremities of temperature. Therefore the main reason deadwooding is carried out
is safety. The situations that usually demand such removal would normally be
trees that overhang public roads, houses, public areas and gardens. Trees that
are located in wooded areas are usually considered and assessed as lower risk
but such assessments would need to consider the amount of visitors. Usually,
trees adjacent to the footpaths and access roads are considered for deadwood
removal. Another reason for deadwooding is amenity value, i.e. a tree with a
large amount of dead throughout the crown looks more aesthetically pleasing with
the deadwood removed. The physical practice of deadwooding can be carried out
most of the year although preferably not when the tree is coming into leaf. The
deadwooding process will speed up the natural abscission process the tree
follows. It will help remove unwanted weight; wind resistance the tree carries
and can help the overall balance.
[edit] Crown and
canopy thinning
Increase light and reduce wind resistance by
selective removal of branches throughout the canopy of the tree. This is a
common practice which improves the tree's strength against adverse weather
conditions as the wind can pass through the tree resulting in less "load" being
placed on the tree.
[edit] Crown canopy
lifting
Crown lifting involves the removal of the lower
branches to a given height. The height is achieved by the removal of whole
branches or removing the parts of branches which extend below the desired
height. The branches are normally not lifted to more than one third of the
tree's total height.
Crown lifting is done for access; these being
pedestrian, vehicle or space for buildings and street furniture. Lifting the
crown will allow traffic and pedestrians to pass underneath safely. This pruning
technique is usually used in the urban environment as it is for public safety
and aesthetics rather than tree form and timber
value.
Crown lifting introduces light to the lower part
of the trunk; this, in some species can encourage epicormic growth from dormant
buds. To reduce this sometimes smaller branches are left on the lower part of
the trunk. Excessive removal of the lower branches can displace the canopy
weight, this will make the tree top heavy, therefore adding stress to the tree.
When a branch is removed from the trunk, it creates a large wound. This wound is
susceptible to disease and decay, and could lead to reduced trunk stability.
Therefore much time and consideration must be taken when choosing the height the
crown is to be lifted to.
This would be an inappropriate operation if the
tree species’ form was of a shrubby nature. This would therefore remove most of
the foliage and would also largely unbalance the tree. This procedure should not
be carried out if the tree is in decline, poor health or dead, dying or
dangerous (DDD) as the operation will remove some of the photosynthetic area the
tree uses. This will increase the decline rate of the tree and could lead to
death.
If the tree is of great importance to an area or
town, (i.e. veteran or ancient) then an alternative solution to crown lifting
would be to move the target or object so it is not in range. For example,
diverting a footpath around a tree’s drip line so the crown lift is not needed.
Another solution would be to prop up or cable-brace the low hanging branch. This
is a non-invasive solution which in some situations can work out more
economically and environmentally friendly.
[edit] Directional
or formative pruning
Removal of appropriate branches to make the tree
structurally sound whilst shaping it.
[edit] Vista
pruning
Selectively pruning a window of view in a
tree.
[edit] Crown
reduction
Reducing the height and or spread of a tree by
selectively cutting back to smaller branches And in fruit trees for increasing
of light interception and enhancing fruit
quality.
[edit]
Pollarding
Main article: Pollarding
A regular form of pruning where certain
deciduous species are pruned back to pollard heads every year in the dormant
period. This practice is usually commenced on juvenile trees so they can adapt
to the harshness of the practice.
[edit] Types of
pruning
Regardless of the various names used for types
of pruning, there are only two basic cuts: One cuts back to an intermediate
point, called heading back cut, and the other cuts back to some point of
origin, called thinning out cut.[1]
Removing a portion of a growing stem down to a
set of desirable buds or side-branching stems. This is commonly performed in
well trained plants for a variety of reasons, for example to stimulate growth of
flowers, fruit or branches, as a preventative measure to wind and snow damage on
long stems and branches, and finally to encourage growth of the stems in a
desirable direction. Also commonly known as
heading-back.
·
Thinning: A more drastic form of pruning, a thinning out
cut is the removal of an entire shoot, limb, or branch at its point of
origin.[1] This is
usually employed to revitalize a plant by removing over-mature, weak,
problematic, and excessive growths. When performed correctly, thinning
encourages the formation of new growth that will more readily bear fruit and
flowers. This is a common technique in pruning roses and for
implifying and "opening-up" the branching of neglected trees, or for
renewing shrubs with multiple branches.
·
Topping: Topping is a very severe form of pruning which
involves removing all branches and growths down to a few large branches or to
the trunk of the tree. When performed correctly it is used on very young trees,
and can be used to begin training younger trees for pollarding or for
trellising to form
an espalier.
·
Raising removes the lower branches from a tree in order to provide clearance
for buildings, vehicles, pedestrians, and
vistas.
·
Reduction reduces the size of a tree, often for clearance
for utility lines. Reducing the height or spread of a tree is best accomplished
by pruning back the leaders and branch terminals to lateral branches that are
large enough to assume the terminal roles (at least one-third the diameter of
the cut stem). Compared to topping, reduction
helps maintain the form and structural integrity of the tree.[2]
In orchards, fruit trees are often lopped to
encourage regrowth and to maintain a smaller tree for ease of picking fruit. The
pruning regime in orchards is more planned and the productivity of each tree is
an important factor.
Deadheading is the act of removing spent flowers or
flowerheads for aesthetics, to prolong bloom for up to several weeks or promote
rebloom, or to prevent seeding.
[edit]
Technique
Some tools utilized for
pruning.
The general rule of pruning is to always cut in
a location where growth will occur, whether the cut is next to a bud or another
branch. Cutting a branch beyond where growth will occur will prevent the plant
from forming a callus over the cut surface, which in turn will invite insects
and infection. It effectively kills all portions of that branch back to the
closest branch, bud, or dormant bud clusters, leaving a stub of dead wood. The
withered stub will eventually rot away and fall off. All cuts should be
relatively smooth since this will aid in
healing.
Also, the pruning cut should not be too large
when compared to the growing point. For instance, a large cut on a 20 cm trunk
down to a 15 cm branch should be fine, but the same cut to the trunk down to a 1
cm twig or bud is considerably less ideal and should be avoided if
possible.
[edit] Pruning to a
bud
A correct pruning cut will allow for quick
healing and promote vigorous growth from the closest bud to the cut. The cut
should be close enough to the bud to reduce the size of the stub of dead wood
that will form from the cut, but far enough away to prevent the bud from being
adversely affected by the cut through desiccation.
Cutting too close to the bud (under-cutting) sometimes results in the death of
the bud, which results in a scenario similar to cutting too far away from the
bud (over-cutting). In general, a correct cut should be angled at a moderate
35-45 degree slant such
that its lowest point is situated on the same level as the tip of the growth
bud. This technique is usually applied when pinching or when
cutting-back.[3]
[edit] Pruning to a
main branch
The pruning cut should occur slightly away from
and follow the branch collar. When cutting away branches growing directly from
the roots, the cut should be flush and level to the ground. This technique is
usually applied when thinning or to remove larger dead or damaged
branches.
When using pruning shears or
loppers to remove a branch back to a main branch, the "hook" portion of the
shears should always face away from the main branch. This ensures that the blade
will not leave a protruding stub and the hook will not damage the branch collar
or parts of the main branch.[4]
[edit] Large heavy
branches
Depending on the weight of the branch, the first
cut should be a notch on the underside of the branch about a third to half of
the way through. The bulk of the branch should then be removed with a
follow-through cut slightly above the first cut, thus leaving a limb stub. The
purpose of this is to stop the weight of the branch from tearing the bark of the
tree from the underside, which would normally occur if the removal was done with
one cut. The limb stub ensures that any cracking of the wood resulting from the
branch separation is limited to the portion of the wood to be removed. The
branch collar should then be located, and can be identified by the strip of
rough bark running down from the topside of the branch at its junction with the
stem. The cut for removing the limb stub should be just outside the branch
collar, leaving a small bump. The bump and the branch collar should not be
removed since this action can increase healing time, which could result in a
major infection.
[edit] Time
period
Pruning small branches can be done at any time
of year. Large branches, with more than 5-10% of the plant's crown, can be
pruned either during dormancy in winter,
or, for species where winter frostcan harm a
recently-pruned plant, in mid summer just after flowering. Autumn should be
avoided, as the spores of disease and decay fungi are abundant
at this time of year.
Some woody plants that tend to bleed profusely
from cuts, such as maples, or which
callous over slowly, such as magnolias, are
better pruned in summer or at the onset of dormancy instead. Woody plants that
flower early in the season, on spurs that form on wood that has matured the year
before, such as apples, should be
pruned right after flowering, as later pruning will sacrifice flowers the
following season. Forsythia, azaleas and
lilacs all fall into this category.
Is selective removal of parts of a plant, parts such as branches buds or even roots.
Types of pruning and why we prune:
To remove deadwood, shape to control growth, improve or maintain health, reduce risk from falling branches, to prepare for transplanting, to increase the quantity of fruit in fruit bearing trees.
Different pruning techniques may be used on different trees and shrubs. Hedges for example are usually controlled with the use of a hedge trimmer rather than by pruning.
The tools of the trade for pruning are hand pruners, loppers, and chainsaws.
In general, the smaller the branch that is cut, the easier it is for a woody plant to compartmentalizethe wound and thus limit the potential for pathogen intrusion and decay. It is therefore preferable to make any necessary formative structural pruning cuts to young plants, when possible, rather than removing large, poorly placed branches from mature plants.
·
1 Pruning landscape and amenity
trees
1.1
Dead-wooding
1.2 Crown and canopy
thinning
1.3
Crown canopy lifting
o
1.4 Directional or formative
pruning
o
1.5
Vista pruning
o
1.6
Crown reduction
o
1.7
Pollarding
·
2
Types of pruning
·
3 Technique
o
3.1
Pruning to a bud
o
3.2 Pruning to a main
branch
o
3.3
Large heavy branches
·
4
Time period
·
5 See also
·
6
References
·
7
External links
[edit] Pruning
landscape and amenity trees
Pruning when there's a branch collar:- Note the swollen area where the branch joins the trunk, this is
known as the collar, do not cut off the collar
Pruning when there's a collarless union:- Note there's no swollen area where the branch joins the trunk, this
is known as a collarless union, cut at a mirror angle to the BBR (branch bark
ridge)
Pruning when it's a codominant stem:- Note the bottom of the BBR and where it meets the outside of the
stem, cut where the red line is.
Branch structure and how they are attached to
each other in trees falls into 3 categories. Collared unions, collarless unions
and codominant unions. Each specific attachment has its own unique way of being
cut so that the branch has less chance of regrowth from the cut area and best
chance of sealing over and compartmentalising decay. This means that there are 3
types of cuts made, whether that be to remove a little branch coming of another
or cutting a whole branch off back to the trunk. This term is often referred to
by arborists as
"target cutting".
Some of the terms used predominantly by
arborists and what they entail:
[edit]
Dead-wooding
Branches die off for a number of reasons ranging
from light deficiency, pests and disease damage to root damage. A dead branch
will at some point decay back to the parent stem causing abscission and fall
off. This is normally a slow process but can be shortened by high winds and
extremities of temperature. Therefore the main reason deadwooding is carried out
is safety. The situations that usually demand such removal would normally be
trees that overhang public roads, houses, public areas and gardens. Trees that
are located in wooded areas are usually considered and assessed as lower risk
but such assessments would need to consider the amount of visitors. Usually,
trees adjacent to the footpaths and access roads are considered for deadwood
removal. Another reason for deadwooding is amenity value, i.e. a tree with a
large amount of dead throughout the crown looks more aesthetically pleasing with
the deadwood removed. The physical practice of deadwooding can be carried out
most of the year although preferably not when the tree is coming into leaf. The
deadwooding process will speed up the natural abscission process the tree
follows. It will help remove unwanted weight; wind resistance the tree carries
and can help the overall balance.
[edit] Crown and
canopy thinning
Increase light and reduce wind resistance by
selective removal of branches throughout the canopy of the tree. This is a
common practice which improves the tree's strength against adverse weather
conditions as the wind can pass through the tree resulting in less "load" being
placed on the tree.
[edit] Crown canopy
lifting
Crown lifting involves the removal of the lower
branches to a given height. The height is achieved by the removal of whole
branches or removing the parts of branches which extend below the desired
height. The branches are normally not lifted to more than one third of the
tree's total height.
Crown lifting is done for access; these being
pedestrian, vehicle or space for buildings and street furniture. Lifting the
crown will allow traffic and pedestrians to pass underneath safely. This pruning
technique is usually used in the urban environment as it is for public safety
and aesthetics rather than tree form and timber
value.
Crown lifting introduces light to the lower part
of the trunk; this, in some species can encourage epicormic growth from dormant
buds. To reduce this sometimes smaller branches are left on the lower part of
the trunk. Excessive removal of the lower branches can displace the canopy
weight, this will make the tree top heavy, therefore adding stress to the tree.
When a branch is removed from the trunk, it creates a large wound. This wound is
susceptible to disease and decay, and could lead to reduced trunk stability.
Therefore much time and consideration must be taken when choosing the height the
crown is to be lifted to.
This would be an inappropriate operation if the
tree species’ form was of a shrubby nature. This would therefore remove most of
the foliage and would also largely unbalance the tree. This procedure should not
be carried out if the tree is in decline, poor health or dead, dying or
dangerous (DDD) as the operation will remove some of the photosynthetic area the
tree uses. This will increase the decline rate of the tree and could lead to
death.
If the tree is of great importance to an area or
town, (i.e. veteran or ancient) then an alternative solution to crown lifting
would be to move the target or object so it is not in range. For example,
diverting a footpath around a tree’s drip line so the crown lift is not needed.
Another solution would be to prop up or cable-brace the low hanging branch. This
is a non-invasive solution which in some situations can work out more
economically and environmentally friendly.
[edit] Directional
or formative pruning
Removal of appropriate branches to make the tree
structurally sound whilst shaping it.
[edit] Vista
pruning
Selectively pruning a window of view in a
tree.
[edit] Crown
reduction
Reducing the height and or spread of a tree by
selectively cutting back to smaller branches And in fruit trees for increasing
of light interception and enhancing fruit
quality.
[edit]
Pollarding
Main article: Pollarding
A regular form of pruning where certain
deciduous species are pruned back to pollard heads every year in the dormant
period. This practice is usually commenced on juvenile trees so they can adapt
to the harshness of the practice.
[edit] Types of
pruning
Regardless of the various names used for types
of pruning, there are only two basic cuts: One cuts back to an intermediate
point, called heading back cut, and the other cuts back to some point of
origin, called thinning out cut.[1]
Removing a portion of a growing stem down to a
set of desirable buds or side-branching stems. This is commonly performed in
well trained plants for a variety of reasons, for example to stimulate growth of
flowers, fruit or branches, as a preventative measure to wind and snow damage on
long stems and branches, and finally to encourage growth of the stems in a
desirable direction. Also commonly known as
heading-back.
·
Thinning: A more drastic form of pruning, a thinning out
cut is the removal of an entire shoot, limb, or branch at its point of
origin.[1] This is
usually employed to revitalize a plant by removing over-mature, weak,
problematic, and excessive growths. When performed correctly, thinning
encourages the formation of new growth that will more readily bear fruit and
flowers. This is a common technique in pruning roses and for
implifying and "opening-up" the branching of neglected trees, or for
renewing shrubs with multiple branches.
·
Topping: Topping is a very severe form of pruning which
involves removing all branches and growths down to a few large branches or to
the trunk of the tree. When performed correctly it is used on very young trees,
and can be used to begin training younger trees for pollarding or for
trellising to form
an espalier.
·
Raising removes the lower branches from a tree in order to provide clearance
for buildings, vehicles, pedestrians, and
vistas.
·
Reduction reduces the size of a tree, often for clearance
for utility lines. Reducing the height or spread of a tree is best accomplished
by pruning back the leaders and branch terminals to lateral branches that are
large enough to assume the terminal roles (at least one-third the diameter of
the cut stem). Compared to topping, reduction
helps maintain the form and structural integrity of the tree.[2]
In orchards, fruit trees are often lopped to
encourage regrowth and to maintain a smaller tree for ease of picking fruit. The
pruning regime in orchards is more planned and the productivity of each tree is
an important factor.
Deadheading is the act of removing spent flowers or
flowerheads for aesthetics, to prolong bloom for up to several weeks or promote
rebloom, or to prevent seeding.
[edit]
Technique
Some tools utilized for
pruning.
The general rule of pruning is to always cut in
a location where growth will occur, whether the cut is next to a bud or another
branch. Cutting a branch beyond where growth will occur will prevent the plant
from forming a callus over the cut surface, which in turn will invite insects
and infection. It effectively kills all portions of that branch back to the
closest branch, bud, or dormant bud clusters, leaving a stub of dead wood. The
withered stub will eventually rot away and fall off. All cuts should be
relatively smooth since this will aid in
healing.
Also, the pruning cut should not be too large
when compared to the growing point. For instance, a large cut on a 20 cm trunk
down to a 15 cm branch should be fine, but the same cut to the trunk down to a 1
cm twig or bud is considerably less ideal and should be avoided if
possible.
[edit] Pruning to a
bud
A correct pruning cut will allow for quick
healing and promote vigorous growth from the closest bud to the cut. The cut
should be close enough to the bud to reduce the size of the stub of dead wood
that will form from the cut, but far enough away to prevent the bud from being
adversely affected by the cut through desiccation.
Cutting too close to the bud (under-cutting) sometimes results in the death of
the bud, which results in a scenario similar to cutting too far away from the
bud (over-cutting). In general, a correct cut should be angled at a moderate
35-45 degree slant such
that its lowest point is situated on the same level as the tip of the growth
bud. This technique is usually applied when pinching or when
cutting-back.[3]
[edit] Pruning to a
main branch
The pruning cut should occur slightly away from
and follow the branch collar. When cutting away branches growing directly from
the roots, the cut should be flush and level to the ground. This technique is
usually applied when thinning or to remove larger dead or damaged
branches.
When using pruning shears or
loppers to remove a branch back to a main branch, the "hook" portion of the
shears should always face away from the main branch. This ensures that the blade
will not leave a protruding stub and the hook will not damage the branch collar
or parts of the main branch.[4]
[edit] Large heavy
branches
Depending on the weight of the branch, the first
cut should be a notch on the underside of the branch about a third to half of
the way through. The bulk of the branch should then be removed with a
follow-through cut slightly above the first cut, thus leaving a limb stub. The
purpose of this is to stop the weight of the branch from tearing the bark of the
tree from the underside, which would normally occur if the removal was done with
one cut. The limb stub ensures that any cracking of the wood resulting from the
branch separation is limited to the portion of the wood to be removed. The
branch collar should then be located, and can be identified by the strip of
rough bark running down from the topside of the branch at its junction with the
stem. The cut for removing the limb stub should be just outside the branch
collar, leaving a small bump. The bump and the branch collar should not be
removed since this action can increase healing time, which could result in a
major infection.
[edit] Time
period
Pruning small branches can be done at any time
of year. Large branches, with more than 5-10% of the plant's crown, can be
pruned either during dormancy in winter,
or, for species where winter frostcan harm a
recently-pruned plant, in mid summer just after flowering. Autumn should be
avoided, as the spores of disease and decay fungi are abundant
at this time of year.
Some woody plants that tend to bleed profusely
from cuts, such as maples, or which
callous over slowly, such as magnolias, are
better pruned in summer or at the onset of dormancy instead. Woody plants that
flower early in the season, on spurs that form on wood that has matured the year
before, such as apples, should be
pruned right after flowering, as later pruning will sacrifice flowers the
following season. Forsythia, azaleas and
lilacs all fall into this category.
