PruningPruningMike Walsh Mike Walsh

Forestry Programs ManagerForestry Programs Manager

Forest ReLeaf of MissouriForest ReLeaf of Missouri

mike@moreleaf.orgmike@moreleaf.org

BackgroundBackground

Mike WalshMike Walsh B.S. Forestry, Missouri 2005B.S. Forestry, Missouri 2005 M.S. Forestry, Missouri 2007M.S. Forestry, Missouri 2007 ISA Certified Arborist 2008 MW-4822AISA Certified Arborist 2008 MW-4822A Worked with the MDC, USDAFS, HARC, & MU Forestry Worked with the MDC, USDAFS, HARC, & MU Forestry

Department conducting research in flood tolerance of MO Department conducting research in flood tolerance of MO hardwoods, controlled black walnut breeding, nursery hardwoods, controlled black walnut breeding, nursery production and more.production and more.

I love trees, learning/teaching about trees, fishing, golfing, I love trees, learning/teaching about trees, fishing, golfing, watching & listening to Cardinals Baseball, Rams watching & listening to Cardinals Baseball, Rams Football?, & Tiger Football (& basketball).Football?, & Tiger Football (& basketball).

Trick Question?Trick Question?

If a tree branch is located five feet If a tree branch is located five feet from the ground, and the tree grows from the ground, and the tree grows 6” each year, how far from the 6” each year, how far from the ground will the branch be in 6 years?ground will the branch be in 6 years?

ObjectivesObjectives

Know why, when and how a tree should be pruned.Know why, when and how a tree should be pruned. Understand how trees respond to pruning and the Understand how trees respond to pruning and the

effects of severe pruning on a tree.effects of severe pruning on a tree. Understand the relationship of the branch collar and Understand the relationship of the branch collar and

branch size to wound closure and the potential for branch size to wound closure and the potential for decay.decay.

Describe the procedures and techniques used in Describe the procedures and techniques used in pruning. Become familiar with the terms used to pruning. Become familiar with the terms used to describe pruning techniques.describe pruning techniques.

Key TermsKey Terms

The Key Terms as listed in The Key Terms as listed in the Arborist’s the Arborist’s Certification Study Certification Study Guide will be defined Guide will be defined and and highlightedhighlighted throughout the throughout the presentation.presentation.

Key Terms - Chapter 8Key Terms - Chapter 8 ANSI 3000 standardsANSI 3000 standards AntigibberellinsAntigibberellins Branch bark ridgeBranch bark ridge Branch collarBranch collar Branch protection zoneBranch protection zone CodominantCodominant CompartmentalizationCompartmentalization Crown cleaningCrown cleaning EspalierEspalier FrondsFronds Heading backHeading back Included barkIncluded bark InternodalInternodal LateralLateral LeaderLeader Lion tailingLion tailing

Permanent branchesPermanent branches Plant growth regulatorsPlant growth regulators PollardingPollarding RaisingRaising ReductionReduction RestorationRestoration Scaffold branchesScaffold branches Structural pruningStructural pruning SubordinateSubordinate Temporary branchesTemporary branches ThinningThinning ToppingTopping Utility pruningUtility pruning Vista pruningVista pruning WatersproutsWatersprouts Wound dressingWound dressing

Introduction to pruningIntroduction to pruning

Why prune?Why prune? Who prunes trees in the woods?Who prunes trees in the woods? Open vs. forested grown treesOpen vs. forested grown trees People reasons – people stresses!People reasons – people stresses!

Health, Safety, & AestheticsHealth, Safety, & Aesthetics

Tree Biology (review)Tree Biology (review) ANSI A300 StandardsANSI A300 Standards

Open Open vs. Forested Growthvs. Forested Growth

Open vs. Open vs. ForestedForested Growth Growth

Why do we prune? 1) HealthWhy do we prune? 1) Health

To maintain the overall health of the treeTo maintain the overall health of the tree Remove broken & diseased branchesRemove broken & diseased branches Rubbing branches / limbs that create woundsRubbing branches / limbs that create wounds Improve taper on branches and limbsImprove taper on branches and limbs Remove codominant stemsRemove codominant stems Attempt to improve overall structure and Attempt to improve overall structure and

health of the tree to reduce the risk of failureshealth of the tree to reduce the risk of failures

Why do we prune? 2) SafetyWhy do we prune? 2) Safety

Trees in high use areas (playgrounds, e.g.)Trees in high use areas (playgrounds, e.g.) Removal of broken and dead material (widow Removal of broken and dead material (widow

makers)makers) Look for poor branch attachments (V-crotches)Look for poor branch attachments (V-crotches) Excessive leaning (may indicate root problems)Excessive leaning (may indicate root problems) Trees in construction areas (10+ year lag time)Trees in construction areas (10+ year lag time) Interference with line of sight on streetsInterference with line of sight on streets Utility pruning (safety of workers, keep the lights on)Utility pruning (safety of workers, keep the lights on) Topped trees (will be a hazard down the road)Topped trees (will be a hazard down the road)

Why do we prune? 3) AestheticsWhy do we prune? 3) Aesthetics

Improve views (vista pruning)Improve views (vista pruning) Provide clearance (car, mowers, pedestrians)Provide clearance (car, mowers, pedestrians)

Pathways & sidewalks to 8’Pathways & sidewalks to 8’ Streets to 15’Streets to 15’

Reduce shade & wind resistanceReduce shade & wind resistance Lawns, groundcovers, mulch beds with flowersLawns, groundcovers, mulch beds with flowers

Influence fruit & flower productionInfluence fruit & flower production

Broken BranchesBroken Branches

Rubbing BranchesRubbing Branches

Codominant StemsCodominant Stems

SafetySafety

Poor Branch AttachmentPoor Branch Attachment

Trees in Power LinesTrees in Power Lines

ClearanceClearance

When to prune?When to prune?(some examples)(some examples)

It depends on the desired results:It depends on the desired results: Maximized growth = early springMaximized growth = early spring Minimize risk of pests and decay = dormant season Minimize risk of pests and decay = dormant season Minimize effects to flowers and fruit = Minimize effects to flowers and fruit =

immediately after floweringimmediately after flowering Timing of year may not always be an optionTiming of year may not always be an option

Storm Damage, e.g.Storm Damage, e.g.

Tree BiologyTree Biology

How a tree growsHow a tree grows Where growth Where growth

occurs in a treeoccurs in a tree ‘‘Types’ of treesTypes’ of trees How this affects How this affects

pruningpruning

Tree BiologyTree Biology

Primary GrowthPrimary Growth

Secondary GrowthSecondary Growth

Branches and Trunk Branches and Trunk AttachmentsAttachments

Excurrent/DecurrentExcurrent/Decurrent

Primary GrowthPrimary Growth

TwigsTwigs StemsStems RootsRoots Terminal BudsTerminal Buds Lateral BudsLateral Buds

Primary GrowthPrimary Growth

Growth of stems, twigs, and roots (elongation)Growth of stems, twigs, and roots (elongation) Terminal buds have apical dominanceTerminal buds have apical dominance Lateral buds near terminal bud stay dormantLateral buds near terminal bud stay dormant

Secondary Secondary GrowthGrowth

Diameter Diameter GrowthGrowth

TaperTaper

Secondary GrowthSecondary Growth Growth from Growth from

cambium for cambium for diameter diameter (expansion)(expansion)

Provides taper Provides taper and strengthand strength

Reaction wood: Reaction wood: formed on stems to formed on stems to

counter leaning counter leaning of the treeof the tree

Branches & Trunk AttachmentsBranches & Trunk Attachments

Branch collarBranch collar

Included barkIncluded bark

Codominant stemsCodominant stems

CrotchesCrotches

Branch collarBranch collar

Branch Collar: area Branch Collar: area where a branch where a branch joins another joins another branch or trunk branch or trunk created by created by overlapping xylem overlapping xylem tissuestissues

Branch Bark RidgeBranch Bark Ridge

Codominant StemsCodominant Stems – forked branches of – forked branches of nearly the same size in diameter and nearly the same size in diameter and

lacking a normal branch unionlacking a normal branch union

Frequent site of Frequent site of structural failure due to structural failure due to included barkincluded bark [bark that [bark that becomes embedded in a becomes embedded in a crotch between branch crotch between branch and trunk or between and trunk or between codominant stems and codominant stems and causes a weak structure]causes a weak structure]

Hmmm…what tree Hmmm…what tree tends to form these?tends to form these?

Included BarkIncluded Bark

Included BarkIncluded Bark

Crotches &Codominant StemsCrotches &Codominant Stems

Excurrent vs. DecurrentExcurrent vs. Decurrent

Know the form a tree will takeKnow the form a tree will take Excurrent: tree growth habit with a pyramid Excurrent: tree growth habit with a pyramid

shaped crown and dominate central leadershaped crown and dominate central leader Examples: sweetgum, tuliptree, most conifersExamples: sweetgum, tuliptree, most conifers

Decurrent: tree growth habit with a rounded or Decurrent: tree growth habit with a rounded or spreading growth habit in the crown spreading growth habit in the crown Examples: most hardwoods like oaks, maples, and Examples: most hardwoods like oaks, maples, and

elmselms

Excurrent vs. DecurrentExcurrent vs. Decurrent

Excurrent vs. DecurrentExcurrent vs. Decurrent

BreakBreak

CODITCODIT

CompartmentalizationCompartmentalization

OfOf

DecayDecay

InIn

TreesTrees

CODITCODIT Wall 1 – Limits vertical Wall 1 – Limits vertical spread of decayspread of decay

Wall 2 – Formed from Wall 2 – Formed from last growth ring and last growth ring and limits spread inwardlimits spread inward

Wall 3 – Composed of Wall 3 – Composed of ray cells that limit lateral ray cells that limit lateral spread of decayspread of decay

Wall 4 – Is the strongest Wall 4 – Is the strongest wall and is the new wall and is the new growth ring that forms growth ring that forms after injuryafter injury

Seven main types of pruningSeven main types of pruning

Structural pruningStructural pruning Pruning to cleanPruning to clean Pruning to restorePruning to restore Crown thinningCrown thinning Crown raisingCrown raising Crown reductionCrown reduction Utility pruningUtility pruning

Structural PruningStructural Pruning Removal of live Removal of live

branches and stems to branches and stems to influence the growth, influence the growth, rate, spacing, strength of rate, spacing, strength of attachments, and attachments, and ultimately the size of the ultimately the size of the branchbranch

Five stepsFive steps

Structural PruningStructural Pruning

1.1. Remove broken, dead, Remove broken, dead, dying or damaged dying or damaged branchesbranches

2.2. Select and establish a Select and establish a dominant dominant leaderleader [the [the primary terminal shoot or primary terminal shoot or trunk of a tree]. trunk of a tree]. Competing stems should Competing stems should be be subordinatedsubordinated [pruning [pruning to reduce the size and to reduce the size and growth of a branch in growth of a branch in relation to other branches relation to other branches or leadersor leaders

Structural PruningStructural Pruning

3.3. Select and establish the Select and establish the lowest lowest permanent branchpermanent branch [branches that will be left [branches that will be left in place, often forming the in place, often forming the initial scaffold framework initial scaffold framework of a tree]of a tree]

4.4. Select and establish Select and establish scaffold branchesscaffold branches [the [the permanent or structural permanent or structural branches of a tree]; 12 -branches of a tree]; 12 -18” spacing depending on 18” spacing depending on the ultimate size of the treethe ultimate size of the tree

Structural PruningStructural Pruning

5.5. Select and subordinate Select and subordinate temporary branchestemporary branches [branches left in place [branches left in place when training young trees; when training young trees; such branches will be such branches will be removed later]removed later]

Why leave them?Why leave them? Proper taperProper taper Prevent SunscaldPrevent Sunscald Energy productionEnergy production

Try to do this over timeTry to do this over time 25% rule25% rule

Pruning to cleanPruning to clean

Removal of Removal of any dead, any dead, broken, and broken, and diseased diseased branchesbranches

Any age and Any age and almost any almost any timetime

Pruning to restorePruning to restore

Select removal of branch, sprouts, and stems Select removal of branch, sprouts, and stems from trees that have been topped, headed, lion from trees that have been topped, headed, lion tailed, or broken in a stormtailed, or broken in a storm

Can take up to several yearsCan take up to several years 1/3 of sprouts removed each year until sprouts 1/3 of sprouts removed each year until sprouts

have developed into brancheshave developed into branches

Crown thinningCrown thinning

Select removal of small live branches to reduce Select removal of small live branches to reduce crown densitycrown density

Increases light penetration and air movementIncreases light penetration and air movement Avoid lion tailing: removal of excessive amount of Avoid lion tailing: removal of excessive amount of

foliage on inner branches and leaves most of foliage foliage on inner branches and leaves most of foliage at end of canopy = weak branchesat end of canopy = weak branches

Never remove more than 25% of the entire crownNever remove more than 25% of the entire crown Water sprouts and sunscald may resultWater sprouts and sunscald may result

Dangers of over-thinningDangers of over-thinning SunscaldSunscald Production of Production of watersproutswatersprouts

[an upright, adventitious [an upright, adventitious shoot arising from the trunk shoot arising from the trunk or branches of a plant; or branches of a plant; although incorrect, it is also although incorrect, it is also called “sucker [shoot arising called “sucker [shoot arising from the roots.”from the roots.”

Lion tailingLion tailing [limbs are [limbs are thinned from the inside of thinned from the inside of the crown to a clump of the crown to a clump of terminal foliage]terminal foliage]

Crown raisingCrown raising

Select removal of branches to provide vertical Select removal of branches to provide vertical clearanceclearance

On younger trees it can reduce taper like lion tailingOn younger trees it can reduce taper like lion tailing On mature trees:On mature trees:

Never remove a branch that is ½ the size of the diameter of Never remove a branch that is ½ the size of the diameter of the trunkthe trunk

Never take away more than 1/3 of the crownNever take away more than 1/3 of the crown Raise limbs by removing small amounts of branches Raise limbs by removing small amounts of branches

at a timeat a time

Crown Crown RaisingRaising – removing lower limbs – removing lower limbs from a tree to provide clearance; from a tree to provide clearance; vistavista

pruningpruning

Crown Crown ReductionReduction

Select removal of Select removal of branches to reduce branches to reduce height/spread of treeheight/spread of tree

25% rule…again!25% rule…again! 1/3 rule too1/3 rule too Clear vegetation away Clear vegetation away

from buildingsfrom buildings Used by utility crewsUsed by utility crews Reduce weightReduce weight NOT TOPPING!!NOT TOPPING!!

Now this is Now this is toppingtopping!!

or heading back, is the or heading back, is the cutting back of a tree to cutting back of a tree to buds, stubs, or laterals buds, stubs, or laterals not large enough to not large enough to assume apical assume apical dominancedominance

Utility PruningUtility Pruning the removal of branches or the removal of branches or

stems to prevent the loss of stems to prevent the loss of service, prevent damage to service, prevent damage to utility equipment, avoid utility equipment, avoid impairment, and uphold the impairment, and uphold the intended usage of utility intended usage of utility facilitiesfacilities

May necessitate pruning May necessitate pruning outside of the scope of outside of the scope of landscape pruning landscape pruning guidelinesguidelines

Maintain ANSI A300 Maintain ANSI A300 standardsstandards

Pruning cutsPruning cuts

Branch removal cutsBranch removal cuts 3 cut method3 cut method

Reduction cutsReduction cuts Improper pruning cuts Improper pruning cuts Wound dressingsWound dressings

Branch removal cutsBranch removal cuts Removal of a branch at its point of origin on the Removal of a branch at its point of origin on the

trunk, stem, or limbtrunk, stem, or limb Use the 3-cut methodUse the 3-cut method

1.) undercut the limb to prevent peeling (>1”)1.) undercut the limb to prevent peeling (>1”) 2.) outside the undercut, begin 22.) outside the undercut, begin 2ndnd cut from top of branch to cut from top of branch to

remove it and leave a stubremove it and leave a stub 3.) final cut is made just outside the branch collar3.) final cut is made just outside the branch collar

Take care not to leave torn bark or jagged edgesTake care not to leave torn bark or jagged edges This allows for This allows for compartmentalizationcompartmentalization [natural [natural

process of defense in trees by which they wall off process of defense in trees by which they wall off decay in the wood ] to occur – NOT HEALING!!decay in the wood ] to occur – NOT HEALING!!

Some more terms…Some more terms… Branch protection zoneBranch protection zone – –

tissues inside the trunk or tissues inside the trunk or parent branch at the base of parent branch at the base of a subordinate branch that a subordinate branch that protect against the spread of protect against the spread of decaydecay

LateralsLaterals [secondary or [secondary or subordinate branch] don’t subordinate branch] don’t compartmentalize as wellcompartmentalize as well

Compartmentalization Compartmentalization ability depends on species, ability depends on species, vigor, climate and size of vigor, climate and size of cut.cut.

Reduction cutsReduction cuts

Removal of stem or branch Removal of stem or branch to a smaller lateral branch to a smaller lateral branch that will assume the that will assume the terminal roleterminal role

Remaining branch should be Remaining branch should be at least 1/3 the diameter of at least 1/3 the diameter of the stem removedthe stem removed

Reducing a lateral should Reducing a lateral should bisect the angle between the bisect the angle between the branch bark ridgebranch bark ridge

Pruning Mature TreesPruning Mature Trees

Factors to consider: site, Factors to consider: site, time of year, species, time of year, species, size, growth habit, size, growth habit, vitality and maturityvitality and maturity

Younger trees are more Younger trees are more tolerant of pruningtolerant of pruning

Consider the size of the Consider the size of the cut…or…one big cut…or…one big branch and the 25% rulebranch and the 25% rule

Improper pruning cutsImproper pruning cuts

Stub cutting, flush cuttingStub cutting, flush cutting

Dressings… not good(?)!Dressings… not good(?)! Once thought to Once thought to

accelerate wound accelerate wound closure and stop/slow closure and stop/slow the spread of decay… the spread of decay… not anymore not anymore

May be beneficial in May be beneficial in reducing borer attack, reducing borer attack, oak wilt infection, or oak wilt infection, or sprout formationsprout formation

More on dressingsMore on dressings

Seal in moisture and decaySeal in moisture and decay Can prevent callus tissue from formingCan prevent callus tissue from forming May inhibit compartmentalizationMay inhibit compartmentalization Has been used to help stop the spread of oak Has been used to help stop the spread of oak

wilt and DEDwilt and DED If used: apply a ligt coating of a non-If used: apply a ligt coating of a non-

phytotoxic material… something water-basedphytotoxic material… something water-based

Specialty PruningSpecialty Pruning

EspalierEspalier – a combination of cutting and training – a combination of cutting and training branches that are oriented in one plane, usually branches that are oriented in one plane, usually supported on a wall, fence or trellissupported on a wall, fence or trellis Used on fruit trees to grow on trellisUsed on fruit trees to grow on trellis

PollardingPollarding – a training system that involves severe – a training system that involves severe heading the first year, and sprout removal annually or heading the first year, and sprout removal annually or every few years to keep large-growing trees to a every few years to keep large-growing trees to a modest size or maintain a formal appearancemodest size or maintain a formal appearance InternodalInternodal – cuts are made at specific locations to begin the – cuts are made at specific locations to begin the

pollarding process.pollarding process. Trivia: Besides aesthetics, why was pollarding done?Trivia: Besides aesthetics, why was pollarding done?

Pruning toolsPruning tools

Why not to top?Why not to top? StarvationStarvation ShockShock Insects & diseasesInsects & diseases Weak limbsWeak limbs Rapid new growthRapid new growth Tree deathTree death UglinessUgliness CostCost

Weak Branch AttachmentWeak Branch Attachment

Plant Growth RegulatorsPlant Growth Regulators

PGR: compounds, effective in small quantities that PGR: compounds, effective in small quantities that affect the growth and development of plantsaffect the growth and development of plants

Antigibberelllins: PGRs that inhibit the action of the Antigibberelllins: PGRs that inhibit the action of the plant hormone gibberellinplant hormone gibberellin

Gibberellin: plant hormones that regulate growth and Gibberellin: plant hormones that regulate growth and influence various developmental processes, including influence various developmental processes, including stem elongation, germination, dormancy, flowering, stem elongation, germination, dormancy, flowering, sex expression, enzyme induction and leaf and fruit sex expression, enzyme induction and leaf and fruit senescencesenescence

Why use PGR? Reduce rotation for utility crews, e.g.Why use PGR? Reduce rotation for utility crews, e.g.

Additional ResourcesAdditional Resources

ANSI A300. Standard Practices for ANSI A300. Standard Practices for Tree, Shrub and Other Woody Plant Tree, Shrub and Other Woody Plant Maintenance, Part 1: PruningMaintenance, Part 1: Pruning

Costello, 2000. Training Young Trees Costello, 2000. Training Young Trees for Structure and Form.for Structure and Form.

Gilman, 1997. An Illustrated Guide to Gilman, 1997. An Illustrated Guide to Pruning Trees.Pruning Trees.

ISA, 1995. Tree Pruning Guidelines.ISA, 1995. Tree Pruning Guidelines.

The endThe end

Questions?Questions?Complaints?Complaints?