HOW to

Prune Trees

NA-FR-01-95

United States

Department of Agriculture

Forest Service 

Northeastern Area

State and Private Forestry

Revised August 2012
How to

Prune Trees

Contents Page

Introduction 1

Reasons for pruning 1

Pruning approaches 4

1. Crown thinning 4

2. Crown raising 7

3. Crown reduction 8

Pruning cuts 10

1. Pruning living branches 10

2. Pruning dead branches 12

3. Drop crotch cuts 13

Pruning practices that harm trees 14

When to prune 16

Pruning tools 17

Treating wounds 20

Pruning guidelines 21

1. General 21

2. Crown thinning 22

3. Crown raising 22

4. Crown reduction 23

Glossary 23

References 26
1

Introduction

The objective of pruning is to produce 

strong, healthy, attractive plants. By 

understanding how, when and why to prune, 

and by following a few simple principles, 

this objective can be achieved. 

Reasons For Pruning

The main reasons for pruning ornamental 

and shade trees include safety, health, and 

aesthetics. In addition, pruning can be used 

to stimulate fruit production and increase 

the value of timber. Pruning for safety (Fig. 

1A) involves removing branches that could 

fall and cause injury or property damage, 

trimming branches that interfere with 

lines of sight on streets or driveways, and 

removing branches that grow into utility 

lines. Safety pruning can be largely avoided 

by carefully choosing species that will not 

grow beyond the space available to them, 

and have strength and form characteristics 

that are suited to the site.

Pruning for health (Fig. 1B) involves 

removing diseased or insect-infested wood, 

thinning the crown to increase airflow and 

reduce some pest problems, and removing 

crossing and rubbing branches. Pruning can 

best be used to encourage trees to develop a 

strong structure and reduce the likelihood 

of damage during severe weather. Removing 

broken or damaged limbs encourages 

wound closure.
2

Figure 1. Reasons for pruning

A. Safety

B. Health

C. Aesthetics
3

Pruning for aesthetics (Fig. 1C) involves 

enhancing the natural form and character 

of trees or stimulating flower production. 

Pruning for form can be especially 

important for open-grown trees that do very 

little self-pruning. 

All woody plants shed branches in response 

to shading and competition. Branches that 

do not produce enough carbohydrates from 

photosynthesis to sustain themselves die and 

are eventually shed; the resulting wounds 

are sealed by woundwood (callus). Branches 

that are poorly attached may be broken off 

by wind and accumulation of snow and ice. 

Branches removed by such natural forces 

often result in large, ragged wounds that 

rarely seal. Pruning as a cultural practice 

can be used to supplement or replace these 

natural processes and increase the strength 

and longevity of plants.

Trees have many forms, but the most 

common types are pyramidal (excurrent) or 

spherical (decurrent). Trees with pyramidal 

crowns, e.g., most conifers, have a strong 

central stem and lateral branches that are 

more or less horizontal and do not compete 

with the central stem for dominance. 

Trees with spherical crowns, e.g., most 

hardwoods, have many lateral branches that 

may compete for dominance.

To reduce the need for pruning it is best 

to consider a tree’s natural form. It is very 

difficult to impose an unnatural form on 

a tree without a commitment to constant 

maintenance.
4

Pollarding and topiary are extreme 

examples of pruning to create a desired, 

unnatural effect. Pollarding is the practice 

of pruning trees annually to remove all new 

growth. The following year, a profusion 

of new branches is produced at the ends 

of the branches. Topiary involves pruning 

trees and shrubs into geometric or animal 

shapes. Both pollarding and topiary are 

specialized applications that involve pruning 

to change the natural form of trees. As 

topiary demonstrates, given enough care 

and attention plants can be pruned into 

nearly any form. Yet just as proper pruning 

can enhance the form or character of plants, 

improper pruning can destroy it.

Pruning Approaches

Producing strong structure should be the 

emphasis when pruning young trees. As 

trees mature, the aim of pruning will shift to 

maintaining tree structure, form, health and 

appearance. 

Proper pruning cuts are made at a node, the 

point at which one branch or twig attaches 

to another. In the spring of the year growth 

begins at buds, and twigs grow until a new 

node is formed. The length of a branch 

between nodes is called an internode. 

The most common types of pruning are:

1. Crown Thinning (Fig. 2)

Crown thinning, primarily for hardwoods, 

is the selective removal of branches to 
5

increase light penetration and air movement 

throughout the crown of a tree. The intent 

is to maintain or develop a tree’s structure 

and form. To avoid unnecessary stress and 

prevent excessive production of epicormic 

sprouts, no more than one-quarter of the 

living crown should be removed at a time. If 

it is necessary to remove more, it should be 

done over successive years.

Figure 2. Crown thinning—branches to be removed 

are shaded in blue; pruning cuts should be made at 

the red lines. No more than one-fourth of the living 

branches should be removed at one time.
6

Branches with strong U-shaped angles of 

attachment should be retained (Fig. 3A). 

Branches with narrow, V-shaped angles 

of attachment often form included bark

and should be removed (Fig. 3B). Included 

bark forms when two branches grow 

at sharply acute angles to one another, 

producing a wedge of inward-rolled bark 

between them. Included bark prevents 

strong attachment of branches, often 

causing a crack at the point below where the 

branches meet. Codominant stems that are 

approximately the same size and arise from 

the same position often form included bark. 

Removing some of the lateral branches from 

a codominant stem can reduce its growth 

enough to allow the other stem to become 

dominant. 

Lateral branches should be no more than 

one-half to three-quarters of the diameter of 

the stem at the point of attachment. Avoid 

producing “lion’s tails,” tufts of branches 

and foliage at the ends of branches, caused 

by removing all inner lateral branches and 

foliage. Lion’s tails can result in sunscalding, 

Figure 3. Types of branch unions

A. U-shaped strong union B. V-shaped weak union
7

abundant epicormic sprouts, and weak 

branch structure and breakage. Branches 

that rub or cross another branch should be 

removed.

Conifers that have branches in whorls 

and pyramidal crowns rarely need crown 

thinning except to restore a dominant leader. 

Occasionally, the leader of a tree may be 

damaged and multiple branches may become 

codominant. Select the strongest leader and 

remove competing branches to prevent the 

development of codominant stems.

2. Crown Raising (Fig. 4) 

Crown raising is the practice of removing 

branches from the bottom of the crown of a 

tree to provide clearance for pedestrians, 

vehicles, buildings, lines of site, or to develop 

a clear stem for timber production. Also, 

removing lower branches on white pines can 

prevent blister rust. For street trees the 

minimum clearance is often specified by 

municipal ordinance. After pruning, the ratio 

of the living crown to total tree height should 

be at least two-thirds (e.g., a 12 m tree should 

have living branches on at least the upper 

8 m).

On young trees “temporary” branches may 

be retained along the stem to encourage 

taper and protect trees from vandalism and 

sunscald. Less vigorous shoots should be 

selected as temporary branches and should 

be about 10 to 15 cm apart along the stem. 

They should be pruned annually to slow their 

growth and should be removed eventually.
8

Figure 4. Crown raising—branches to be removed are 

shaded in blue; pruning cuts should be made where 

indicated with red lines. The ratio of live crown to total 

tree height should be at least two-thirds.

3. Crown Reduction (Fig. 5)

Crown reduction pruning is most often 

used when a tree has grown too large for its 

permitted space. This method, sometimes

called drop crotch pruning, is preferred to 

topping because it results in a more natural 

appearance, increases the time before pruning 

is needed again, and minimizes stress (see 

drop crotch cuts in the next section).

Crown reduction pruning, a method of last 

resort, often results in large pruning wounds 

retain

67%

crown

prune

33%
9

to stems that may lead to decay. This method 

should never be used on a tree with a 

pyramidal growth form. A better long term 

solution is to remove the tree and replace 

it with a tree that will not grow beyond the 

available space.

Figure 5. Crown reduction—branches to be removed 

are shaded in blue; pruning cuts should be made 

where indicated with red lines. To prevent branch 

dieback, cuts should be made at lateral branches that 

are at least one-third the diameter of the stem at their 

union.
10

Pruning Cuts

Pruning cuts should be made so that only 

branch tissue is removed and stem tissue is 

not damaged. At the point where the branch 

attaches to the stem, branch and stem tissues 

remain separate, but are contiguous. If only 

branch tissues are cut when pruning, the 

stem tissues of the tree will probably not 

become decayed, and the wound will seal 

more effectively.

1. Pruning living branches (Fig. 6)

To find the proper place to cut a branch, 

look for the branch collar that grows from 

the stem tissue at the underside of the 

base of the branch (Fig. 6A). On the upper 

surface, there is usually a branch bark 

ridge that runs (more or less) parallel to the 

branch angle, along the stem of the tree. A 

proper pruning cut does not damage either 

the branch bark ridge or the branch collar.

A proper cut begins just outside the branch 

bark ridge and angles down away from 

the stem of the tree, avoiding injury to the 

branch collar (Fig. 6B). Make the cut as close 

as possible to the stem in the branch axil, 

but outside the branch bark ridge, so that 

stem tissue is not injured and the wound 

can seal in the shortest time possible. If 

the cut is too far from the stem, leaving 

a branch stub, the branch tissue usually 

dies and woundwood forms from the stem 

tissue. Wound closure is delayed because the 

woundwood must seal over the stub that was 

left.
11

The quality of pruning cuts can be evaluated 

by examining pruning wounds after one 

growing season. A concentric ring of 

woundwood will form from proper pruning 

Figure 6. Pruning cuts

A. Targeting the cut

B. Cutting a small branch C. Cutting a larger branch

D. Crown reduction cut

dead

branch

branch collar

branch

bark

ridge

branch

bark ridge

final

cut

final

cut

final

cut

2nd

cut

2nd cut

1st

cut

1st cut

branch collar

living

branch
12

cuts (Fig. 6B). Flush cuts made inside the 

branch bark ridge or branch collar, result in 

pronounced development of woundwood 

on the sides of the pruning wounds with 

very little woundwood forming on the top 

or bottom (Fig. 7D). As described above, 

stub cuts result in the death of the remaining 

branch and woundwood forms around the 

base from stem tissues.

When pruning small branches with hand 

pruners, make sure the tools are sharp 

enough to cut the branches cleanly without 

tearing. Branches large enough to require 

saws should be supported with one hand 

while the cuts are made. If the branch is too 

large to support, make a three-step pruning 

cut (Fig. 6C) to prevent bark ripping

(Fig. 7C).

1. The first cut is a shallow notch made 

on the underside of the branch, 

outside the branch collar. This cut 

will prevent a falling branch from 

tearing the stem tissue as it pulls 

away from the tree.

2. The second cut should be outside 

the first cut, all the way through the 

branch, leaving a short stub. 

3. The stub is then cut just outside the 

branch bark ridge/branch collar, 

completing the operation.

2. Pruning dead branches (Fig. 6)

Prune dead branches in much the same 

way as live branches. Making the correct 

cut is usually easy because the branch 
13

collar and the branch bark ridge, can be 

distinguished from the dead branch, because 

they continue to grow (Fig. 6A). Make 

the pruning cut just outside of the ring of 

woundwood tissue that has formed, being 

careful not to cause unnecessary injury 

(Fig. 6C). Large dead branches should be 

supported with one hand or cut with the 

three-step method, just as live branches. 

Cutting large living branches with the threestep method is more critical because of the 

greater likelihood of bark ripping.

3. Drop Crotch Cuts (Fig. 6D)

A proper cut begins just above the branch 

bark ridge and extends through the stem 

parallel to the branch bark ridge. Usually, 

the stem being removed is too large to be 

supported with one hand, so the three-cut 

method should be used.

1. With the first cut, make a notch on 

the side of the stem away from the 

branch to be retained, well above the 

branch crotch.

2. Begin the second cut inside the 

branch crotch, staying well above the 

branch bark ridge, and cut through 

the stem above the notch.

3. Cut the remaining stub just inside 

the branch bark ridge through the 

stem parallel to the branch bark 

ridge.

To prevent the abundant growth of 

epicormic sprouts on the stem below the 

cut, or dieback of the stem to a lower lateral 
14

branch, make the cut at a lateral branch that 

is at least one-third of the diameter of the 

stem at their union. 

Pruning Practices That Harm 

Trees

Topping and tipping (Fig. 7A, 7B) are 

pruning practices that harm trees and 

should not be used. Crown reduction 

pruning (Fig. 5) is the preferred method to 

reduce the size or height of the crown of a 

tree, but is rarely needed and should be used 

infrequently.

Topping, the pruning of large upright 

branches between nodes, is sometimes 

done to reduce the height of a tree (Fig. 

7A). Tipping is a practice of cutting lateral 

branches between nodes (Fig. 7B) to reduce 

crown width. 

These practices invariably result in the 

development of epicormic sprouts, or in 

the death of the cut branch back to the 

next lateral branch below. These epicormic 

sprouts are weakly attached to the stem and 

eventually will be supported by a decaying 

branch.

Improper pruning cuts cause unnecessary 

injury and bark ripping (Fig. 7C). Flush cuts

injure stem tissues and can result in decay 

(Fig. 7D). Stub cuts delay wound closure 

and can provide entry to canker fungi that 

kill the cambium, delaying or preventing 

woundwood formation (Fig. 7E). 
15

Figure 7. Practices that harm trees

A. Topping

C. Bark ripping D. Flush cutting

E. Stub cutting

B. Tipping
16

When to Prune 

Conifers may be pruned any time of year, 

but pruning during the dormant season 

may minimize sap and resin flow from cut 

branches.

Hardwood trees and shrubs without showy 

flowers: prune in the dormant season to 

easily visualize the structure of the tree, to 

maximize wound closure in the growing 

season after pruning, to reduce the chance 

of transmitting disease, and to discourage 

excessive sap flow from wounds. Recent 

wounds and the chemical scents they emit 

can actually attract insects that spread tree 

disease. In particular, wounded elm wood 

is known to attract bark beetles that harbor 

spores of the Dutch elm disease fungus, and 

open wounds on oaks are known to attract 

beetles that spread the oak wilt fungus. Take 

care to prune these trees during the correct 

time of year to prevent spread of these fatal 

diseases. Contact your local tree disease 

specialist to find out when to prune these 

tree species in your area. Usually, the best 

time is during the late fall and winter.

Flowering trees and shrubs: these should 

also be pruned during the dormant season 

for the same reasons stated above; however, 

to preserve the current year’s flower crop, 

prune according to the following schedule:

 Trees and shrubs that flower in early 

spring (redbud, dogwood, etc.) 

should be pruned immediately after 
17

flowering (flower buds arise the year 

before they flush, and will form on 

the new growth).

 Many flowering trees are susceptible 

to fireblight, a bacterial disease that 

can be spread by pruning. These 

trees, including many varieties 

of crabapple, hawthorn, pear, 

mountain ash, flowering quince 

and pyracantha, should be pruned 

during the dormant season. Check 

with your county extension agent 

or a horticulturist for additional 

information.

 Trees and shrubs that flower in the 

summer or fall always should be 

pruned during the dormant season 

(flower buds will form on new twigs 

during the next growing season, and 

the flowers will flush normally).

Dead branches: can be removed any time of 

the year.

Pruning Tools 

Proper tools are essential for satisfactory 

pruning (Fig. 6). The choice of which tool to 

use depends largely on the size of branches 

to be pruned and the amount of pruning to 

be done. If possible, test a tool before you 

buy it to ensure it suits your specific needs. 

As with most things, higher quality often 

equates to higher cost.
18

Generally speaking, the smaller a branch is 

when pruned, the sooner the wound created 

will seal. Hand pruners are used to prune 

small branches (under 2.5 cm diameter) and 

many different kinds are available. Hand 

pruners can be grouped into bypass or anvil 

styles based on the blade configuration. 

Anvil style pruners have a straight blade 

that cuts the branch against a small anvil or 

block as the handles are squeezed. Bypass 

pruners use a curved cutting blade that 

slides past a broader lower blade, much like 

a scissors. To prevent unnecessary tearing or 

crushing of tissues, it is best to use a bypass 

style pruner. Left- or right-handed types can 

be purchased.

Slightly larger branches that cannot be cut 

with a hand pruner may be cut with small 

pruning saws (up to 10 cm) or lopping 

shears (up to 7 cm diameter) with larger 

cutting surfaces and greater leverage. 

Lopping shears are also available in bypass 

and anvil styles.

For branches too large to be cut with a hand 

pruner or lopping shears, pruning saws 

must be used. Pruning saws differ greatly 

in handle styles, the length and shape of the 

blade, and the layout and type of teeth. Most 

have tempered metal blades that retain their 

sharpness for many pruning cuts. Unlike 

most other saws, pruning saws are often 

designed to cut on the “pull-stroke.”

Chain saws are preferred when pruning 

branches larger than about 10 cm. Chain 

saws should be used only by qualified 
19

individuals. To avoid the need to cut 

branches greater than 10 cm diameter, prune 

when branches are small.

Pole pruners must be used to cut branches 

beyond reach. Generally, pruning heads 

can cut branches up to 4.4 cm diameter and 

are available in the bypass and anvil styles. 

Once again, the bypass type is preferred. 

For cutting larger branches, saw blades can 

be fastened directly to the pruning head, 

or a separate saw head can be purchased. 

Because of the danger of electrocution, pole 

pruners should not be used near utility lines, 

except by qualified utility line clearance 

personnel.

To ensure that satisfactory cuts are made 

and to reduce fatigue, keep your pruning 

tools sharp and in good working condition. 

Hand pruners, lopping shears, and pole 

pruners should be periodically sharpened 

with a sharpening stone. Replacement 

blades are available for many styles. Pruning 

saws should be professionally sharpened or 

periodically replaced. To reduce cost, many 

styles have replaceable blades.

Tools should be clean and sanitized as well 

as sharp. Although sanitizing tools may be 

inconvenient and seldom practiced, doing so 

may prevent the spread of disease from 

infected to healthy trees on contaminated 

tools. Tools become contaminated when 

they come into contact with fungi, bacteria, 

viruses and other microorganisms that cause 

disease in trees. Most pathogens need some 

way of entering the tree to cause disease, and 
20

fresh wounds are perfect places for 

infections to begin. Microorganisms on tool 

surfaces are easily introduced into 

susceptible trees when subsequent cuts are 

made. The need for sanitizing tools can be 

greatly reduced by pruning during the 

dormant season.

If sanitizing is necessary it should be 

practiced as follows: before each branch 

is cut, sanitize pruning tools with either 

70% denatured alcohol, or with liquid 

household bleach diluted 1 to 9 with water 

(1 part bleach, 9 parts water). Tools should 

be immersed in the solution, preferably for 

1-2 minutes, and wood particles should be 

wiped from all cutting surfaces. Bleach is 

corrosive to metal surfaces, so tools should 

be thoroughly cleaned with soap and water 

after each use.

Treating Wounds

Tree sap, gums, and resins are the natural 

means by which trees combat invasion by 

pathogens. Although unsightly, sap flow 

from pruning wounds is not generally 

harmful; however, excessive “bleeding” can 

weaken trees. 

When oaks or elms are wounded during a 

critical time of year (usually spring for oaks, 

or throughout the growing season for elms) 

— either from storms, other unforeseen 

mechanical wounds, or from necessary 

branch removals — some type of wound 

dressing should be applied to the wound. 
21

Do this immediately after the wound is 

created. In most other instances, wound 

dressings are unnecessary, and may even 

be detrimental. Wound dressings will not 

stop decay or cure infectious diseases. They 

may actually interfere with the protective 

benefits of tree gums and resins, and prevent 

wound surfaces from closing as quickly as 

they might under natural conditions. The 

only benefit of wound dressings is to prevent 

introduction of pathogens in the specific

cases of Dutch elm disease and oak wilt. 

Pruning Guidelines

To encourage the development of a strong, 

healthy tree, consider the following 

guidelines when pruning.

1. General

 Prune first for safety, next for health, 

and finally for aesthetics.

 Never prune trees that are touching 

or near utility lines; instead consult 

your local utility company.

 Avoid pruning trees when you might 

increase susceptibility to important 

pests (e.g., in areas where oak wilt 

exists, avoid pruning oaks in the 

spring and early summer; prune 

trees susceptible to fireblight only 

during the dormant season).

 Use the following decision guide for 

size of branches to be removed: 
22

1) under 5 cm diameter - go ahead,

2) between 5 and 10 cm diameter - 

think twice, and 3) greater than 10 

cm diameter - have a good reason.

2. Crown Thinning

 Assess how a tree will be pruned 

from the top down.

 Favor branches with strong, 

U-shaped angles of attachment. 

Remove branches with weak, 

V-shaped angles of attachment

and/or included bark.

 Ideally, lateral branches should be 

evenly spaced on the main stem of 

young trees.

 Remove any branches that rub or 

cross another branch.

 Make sure that lateral branches are 

no more than one-half to threequarters of the diameter of the stem 

to discourage the development of 

co-dominant stems.

 Do not remove more than onequarter of the living crown of a 

tree at one time. If it is necessary to 

remove more, do it over successive 

years. 

3. Crown Raising

 Always maintain live branches 

on at least two-thirds of a tree’s 

total height. Removing too many 

lower branches will hinder the 

development of a strong stem.
23

 Remove basal sprouts and vigorous 

epicormic sprouts.

4. Crown Reduction

 Use crown reduction pruning only 

when absolutely necessary. Make the 

pruning cut at a lateral branch that is 

at least one-third the diameter of the 

stem to be removed.

 If it is necessary to remove more 

than half of the foliage from a 

branch, remove the entire branch.

Glossary

Branch Axil: the angle formed where a 

branch joins another branch or stem of a 

woody plant.

Branch Bark Ridge: a ridge of bark that 

forms in a branch crotch and partially 

around the stem resulting from the growth 

of the stem and branch tissues against one 

another.

Branch Collar: a “shoulder” or bulge 

formed at the base of a branch by the annual 

production of overlapping layers of branch 

and stem tissues.

Crown Raising: a method of pruning to 

provide clearance for pedestrians, vehicles, 

buildings, lines of sight, and vistas by 

removing lower branches.
24

Crown Reduction Pruning: a method of 

pruning used to reduce the height of a tree. 

Branches are cut back to laterals that are 

at least one-third the diameter of the limb 

being removed.

Crown Thinning: a method of pruning to 

increase light penetration and air movement 

through the crown of a tree by selective 

removal of branches.

Callus: see woundwood.

Decurrent: a major tree form resulting 

from weak apical control. Trees with this 

form have several to many lateral branches 

that compete with the central stem for 

dominance resulting in a spherical or 

globose crown. Most hardwood trees have 

decurrent forms.

Epicormic Sprout: a shoot that arises from 

a latent or adventitious bud. Epicormic 

sprouts are also known as water sprouts that 

grow from stems and branches, and suckers 

that are produced from the base of trees. In 

older wood, epicormic shoots often result 

from severe defoliation or radical pruning.

Excurrent: a major tree form resulting from 

strong apical control. Trees with this form 

have a strong central stem and pyramidal 

shape. Lateral branches rarely compete 

for dominance. Most conifers and a few 

hardwoods, such as sweetgum and tuliptree, 

have excurrent forms.
25

Flush Cuts: pruning cuts that originate 

inside the branch bark ridge or the branch 

collar, causing unnecessary injury to stem 

tissues.

Included Bark: bark enclosed between 

branches with narrow angles of attachment, 

forming a wedge between the branches.

Pollarding: the annual removal of all of the 

previous year’s growth, resulting in a flush of 

slender shoots and branches each spring.

Stub Cuts: pruning cuts made too far 

outside the branch bark ridge or branch 

collar, that leave branch tissue attached to 

the stem.

Tipping: a poor maintenance practice used 

to control the size of tree crowns; involves 

the cutting of branches at right angles 

leaving long stubs.

Topping: a poor maintenance practice often 

used to control the size of trees; involves 

the indiscriminate cutting of branches and 

stems at right angles leaving long stubs. 

Synonyms include rounding-over, headingback, dehorning, capping and hat-racking. 

Topping is often improperly referred to as 

pollarding.

Topiary: the pruning and training of a plant 

into a desired geometric or animal shape.

Woundwood: lignified, differentiated tissues 

produced on woody plants as a response to 

wounding (also known as callus tissue).
26

References

ANSI Z133.1. 1994. Safety standards. 

American national standard for tree care 

operators. Washington, DC: American 

National Standards Institute.

ANSI A300. 1995. Standard practices 

for tree, shrub, and other woody 

plant maintenance. Washington, DC: 

American National Standards Institute.

Fazio, J. R. ed. 1992. Don’t top trees. Tree 

City USA Bulletin No. 8. Nebraska 

City, NE: The National Arbor Day 

Foundation.

Harris, R.W. 1994. Clarifying certain 

pruning terminology: thinning, heading, 

pollarding. Journal of Arboriculture 

20:50-54.

ISA Performance Guidelines Committee. 

1994. Tree-pruning guidelines. Savoy, IL: 

International Society of Arboriculture.

Ryan, H.D.P. III. 1994. Arboricultural 

pruning methodologies. Arborist News 

Volume 3(4):33-38.

Shigo, A. 1991. Modern arboriculture. 

Durham, NH: Shigo & Trees, Associates.

Shigo, A. 1989. Tree pruning: a worldwide 

photo guide. Durham, NH: Shigo & 

Trees, Associates.
27

Notes:
28

“How to Prune Trees” was written to help 

people properly prune the trees they care 

about. If you doubt your ability to safely 

prune large trees, please hire a professional 

arborist. Information in this publication can 

be used to interview and hire a competent 

arborist.

Northeastern Area State & Private 

Forestry Offices:

Headquarters Office

Northeastern State & Private Forestry

USDA Forest Service

11 Campus Boulevard, Suite 200

Newtown Square, Pennsylvania 19073

Durham Field Office

Northeastern Area State & Private Forestry

USDA Forest Service

271 Mast Road

Durham, New Hampshire 03824-9799

Morgantown Field Office

Northeastern Area State & Private Forestry

USDA Forest Service

180 Canfield Street

Morgantown, West Virginia 26505-3101

St. Paul Field Office

Northeastern Area State & Private Forestry

USDA Forest Service

1992 Folwell Avenue

St. Paul, Minnesota 55108-1099
29

Authors

Peter J. Bedker, Plant Pathologist, USDA 

Forest Service, Northeastern Area State 

and Private Forestry

Joseph G. O’Brien, Plant Pathologist, USDA 

Forest Service, Northeastern Area State 

and Private Forestry

Manfred E. Mielke, Forest Health Specialist, 

USDA Forest Service, Northeastern Area 

State and Private Forestry

Illustrations by:

Julie Janke, Scientific Illustrator, Afton, 

Minnesota

For Further Information, Contact:
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programs.) Persons with disabilities who require alternative means 

for communication of program information (Braille, large print, 

audiotape, etc.) should contact USDA’s TARGET Center at (202) 

720-2600 (voice and TDD). To file a complaint of discrimination, 

write to USDA, Director, Office of Civil Rights, 1400 Independence 

Avenue, S.W., Washington, D.C. 20250-9410, or call (800) 795-3272 

(voice) or (202) 720-6382 (TDD). USDA is an equal employment 

opportunity provider and employer.