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Maintaining Trees

to Last a Life Time

Richard J Hauer Ph DRichard J. Hauer, Ph.D

Associate Professor of Urban ForestryCollege of Natural Resources, University of Wisconsin – Stevens Point

• Provide Shade

• Attract Wildlife

• Food Source

Why Do People Plant Trees?

• Green the Grey Infrastructure

• Complement Architecture

• Business Activity

• Landscaping

• Future Value

• Screen View

Often a Design Question … Often a utilitarian purpose!

• Outdoor Room

• Why Not

• And More …

Why do people build in forests?

Factor with buying wooded lot Index Score1

Presence of trees on property 4.74

Country-like atmosphere 4.23

Resale value 4.10

Species of trees on property 3 67Species of trees on property 3.67

Architecture of house 3.51

Location relation to urban center 3.44

Bank loan accessibility 3.27

1 Index Score: Strongly agree = 5, Agree = 4, Neutral = 3, Disagree = 2, Strongly disagree = 1 (Vander Weit and Miller 1986)

What Do People Expect… The Utopian Urban Forest

The Youth become >>>>>>>>>>>>>>>> >>>>> The Centurion's of the Urban Forest

People Don’t Expect

Declining & dead before age 20 years

• Sidewalk cutout 10 years (Foster 1988)

• American forests suggested (1990)…– Down town tree 7 or 13 years– Suburb Residential 32 years– Park trees 60 years– Rural Forest 150+ years

Mean Life Spans of Trees. Show me the data

• Urban infrastructure repair (2008)– Buried utilities last 30 years (Memphis Light, Gas & Water 2008)

– Roads, curbs, sidewalks 20 – 40 years (National Research Council Canada 2008)

• Construction study (Hauer 2008 )

Treatment 1979 2005 Survival (%)

Construction 432 275 63.7

Control 413 265 64.2

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• Douglas-fir 700 – 1275

• Yellow Buckeye 430

• Sugar maple 300 – 400

• American beech 300 – 400

• Black Walnut 250

Potential Life Spans of Trees (Years). Show me the data

Black Walnut 250

• Silver Maple 125

• Boxelder rarely 100

• Jack Pine 60 – 150

Source: Textbook of Dendrology 9th Edition (2001)

900 Year Old Oak

City Trees Genetic Potential Like Forest Trees?

Approximately 119 years old

4536 Minnehaha Ave South

August, 2007

R² = 0.7654

0

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40

60

80

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120

140

0 50 100 150

db

h (

cm)

Age

American Elm - Age to dbh biometrics

DBH cm

Linear (DBH cm)

How to Kill a Tree in One Hundred and Ten Years?

Plant … Establish … Let nature and brown rot take it’s course!

How to Kill a Tree Without Trying

Shocking truth, even the best plans get modified!

Photo by Bill Vander Weit

• Be creative in your assisted Arboricide

• Match the wrong tree for site

• Find the worst planting stock

• Plant them trees deep

• Ignore establishment needs

How to Kill a Tree in Four Years?

The Decline or Mortality Spiral

( C

Why do trees fail?

(Tree Disease Concepts, Paul Manion1981)

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Meet the Geno and Pheno Type Family

Mrs. Pheno TypeMr. Geno Type

Tilia tilted Type “their fallen son”

They had a Child …

Which Type do You Want?

Geno + Pheno Type = What you Get

Is this what you want?

They also had a Daughter Acer samara Type ‘Centurian’

Trees, Size, Benefits, and Longevity? Trees, Size, Benefits, and Longevity?

The Champ is on the ropes

• How many years before benefits = costs of tree planting?

– Public housing sites 9 years

– Yard/street trees 13-14 years

Benefits of Trees … Benefit of Time

– Parks & highways 15 years

• All sites Chicago region (McPherson 1993, GTR NE-186)

Tree payback … break even time in different locations

Environmental Constraints

Edaphic

Climatic

Physiographic

Biologic

Site Factors

Cultural Constraints

Utilities

Structures

Surface Cover

Pollution

Selecting Trees: Arbor Husbandry & Site Evaluation

Species Selection

Social Factors

Aesthetic

Functional

Utility

Negative Externalities

Economic FactorsEstablishment Costs

Maintenance Costs

Removal Costs

Species Selection Model (Miller 1998)

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• Cold Tolerance

Selecting Trees: Hardiness Zones and Tolerance

• Heat Tolerance

• Urban soils often become or are alkaline– Infrastructure and soil alterations

– Conduct pH tests and keep records

• General considerations

Selecting Trees: Soil pH

• General considerations– Below 5.0 is acidic soil

– 5.5 – 6.5 is mildly acidic

– 6.5 to ~ 7.2 becoming alkaline

– >7.2 – 7.3 and more, considered as alkaline

Selecting Trees: Design for Final Size (Image by James Urban)

Restricted Planting Sites, Try Small Stature Trees

Selecting Trees: Design for Decline

Trees planted ~ 1988 and look similar in 1998

In this corner …

Pit versus Vault

Green versus Grey

Selecting Trees: Design for Decline

De-energized in 2010 Energizer Trees in 2010

Selecting Trees: Design for Final Size

19 year-old trees 19 day-old concrete

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Sidewalk-Tree Conflicts

Inappropriate Species

and … or

Poor Infrastructure

Design?

What are the solutions to this design?

Avoid

sidewalk conflict with

Selecting Trees: Tree Literate Spacing

> 4-6’ if root/trunk

collarpossible

Species dependent … in general > 4 – 6 feet

Selecting Trees: Conventional Practice or Alternative

Alternative: Green easementConventional: Narrow tree lawn

Selecting Trees: Sometimes you get lucky

Bio … logical Urban Forests

Innovations in Arboriculture

Devine Intervention (Photos by Joe Hoffman)

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Innovations in Hot Tubs

Do Not Try This at Home, Professional Stuntmen

Innovations in Planting Trees

Shovel, backhoe, stump grinder, log loader, auger, …

Planting Trees: Many production and holding systems

B&B and HorsesBare root & container

Planting Trees: Many different ways

Poor Better Best

Planting Trees: Don’t plant deep and proud Planting Trees: The conventional way

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Neededor

Not?

Planting Trees: Is new way better than old way?

Not?

Depends!

Soil Bulk Density

• What is bulk density?– Mass per volume soil (g/cm3 or Mg/M3)

– What does it really mean?• Granite ~ 2.65 g/cm3

• 1.4 – 1.6 g/cm3 critical value

– Forest soils maybe ~ 0.8

Planting Trees: Soil Compaction Studies

Forest soils maybe 0.8

• Compaction study (Lichter and Lindsey 1993)

– Mass graded sites 1.75 g/cm3

– Control 1.27 versus 1.61 outside fencing– Control 0.95 versus 1.14 inside fenced area

• As BD increases OM, air, and water decrease

• Tree root growth impeded – Sand Soils > 1.75 g/cm3

Clay Soils > 1 55 g/cm3

Planting Trees: Soil Compaction Studies

– Clay Soils > 1.55 g/cm3

• Species differences and root penetration– Lodgepole pine 1.32 g/cm3

– Red Alder 1.59 g/cm3

– Prostrate knotweed 1.9 g/cm3

Planting Trees: Good Intentions Gone Bad

Plant ‘em high – watch ‘em die! Plant ‘em low, won’t grow (Eric Draper)

Planted Tree: Just when they are getting big

Stem Girdling Roots

True or False

“…a tree gains a new ring every year.”

“never enter the stem deeper than you

Tree Care: Based on Science & Observation

John Evelyn (1664): Sylva, or a discourse of forest trees

never enter the stem deeper than you found it; for profound burying very frequently destroys a tree.”

Both True and Long Known

John Evelyn (1664): Sylva, or a discourse of forest trees

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You Can Only

Correct So Much!

Measuring a B&B root ball.

Root Depth Check (Watson 2005)

Figure 3. The root system will be undersized if the roots are more than 3 inches deep in the root ball

Figure 1. At least 2 structural roots should be within 1 to 3 inches of the soil surface, measured 3-4 inches from the trunk.

Stem Diameter (mm)

Years After

Planting

Planted at

Grade

Buried 3

Inches

Percentage

Growth

Reduction

Planting Trees: Ash and Buried Root Systems (Arnold et al. 2005)

0 15 15 0

1 20 17 15

2 29 19 34

3 36 23 36

Plant ‘em low, won’t grow

Which Type do You Want?

Tilia tilted Type “their fallen son”Acer samara

Type ‘Centurian’

Planting Trees: Trees holding systems have a shelf life

Look for signs … deteriorating burlap

Planting Trees: Trees have a shelf life

Look for signs … Sale on Trees, 50% Off

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Planting Trees: Steps to Take

How Deep to Dig? The Final Resting Spot!

Planting Trees: Steps to Take

Remove Packaging, Remove Excess, Fill Hole, & Water

Planting Trees: What about containers? (Photos by Dave Hanson)

Remove soil to structural rootsAssume buried, not always, determine

Planting Trees: What about containers? (Photos by Dave Hanson)

Boxing or Shaving pot bound plant

Remove stem girdling root

Planting: Wire baskets an issue? Science and Opinion

Wire baskets are resilient!Is root girdling a tree killer?

Planting: Rope and wire girdling of stems does kill

Staking (above) & Labels (below) B&B twine & packaging twine

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• If you do

• Wide strap

Planting: Is staking needed?

This … Wide Band

• Let it sway

• Remove one year

Stake and Shake

Not This … Tight and Narrow

Wind, Stress, and Tree Response

Extreme Taper Makeover: Tree Edition

Advancements in Arboriculture

Trees holding up stakes? What’s holding what

Tree Planting: Pruning at Planting (Walmsely 1985)

No Evidence Compensatory Pruning is Beneficial

• Broken and weak branches

• Competing leaders

• Branches with narrow crotch angles

Di d d

Tree Planting: Corrective Pruning at Planting

• Diseased wood

• Crossing branches

• Branches that detract from the shape

What to Remove

• June Cleaver “Ward, I’m very worried about the Beaver”

• The Wonder Years: “Growing up happens in a heartbeat. One day you’re in diapers, the next day you’re gone. But the memories of childhood stay with you for the long haul.”

Establishment and the Formative Years

• That 70’s Show: Burn: two parts – (1) You didn’t see it coming and (2) parts of it really hurt.

Prevention usually cheaper than correction

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Establishment: Don’t set it and forget it

I am a chicken I am a tree

Smaller trees establish sooner

Smaller trees cost less

Easier to handle

Easier to get snapped

Economics of Establishment

Bare Root 1” B&B 2.5”

General Establishment Rule for Upper Midwest

1 year per stem dia. inch

Sugar maple trees 5 years later

USDA Hardiness Zone

Diameter

(inch) 5 6 7 8 9 10

1 12 10 7 5 3 3

Establishment: Tree size, hardiness zone, & time (months)

2 24 20 15 10 6 6

3 36 30 23 16 9 9

4 48 39 30 21 12 12

(Gilman 1997, Trees for Urban & Suburban Landscapes)

Establishment: Indicators

Reduced twig and needle growth

Water deficits and multiple leaders

Establishment: Indicators

Canopy and Twig Dieback

Wilt (above) & abnormal leaf size (Photos, Gary Johnson)

Establishment: Water Deficits, Sunscald and Borers

What came first the chicken or the sunscald?

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Establishment: Water Dosage and Frequency Establishment: Water and Plant Growth (Gilman J. Arbor 2001)

Number of Trees PercentTreatment Planted Dead SurvivalPlastic container 14 6 57Plastic container with SpinOut 14 8 43Air root-pruning (ARP) 14 7 50Low-profile ARP container 14 10 29Root-pruned, field-grown B&B 14 0 100Non root pruned field grown B&B 14 4 71

Establishment: Water & Economics 101 (Gilman J. Arbor 2001)

Non-root-pruned, field-grown B&B 14 4 71

Cost per live treeTreatment Irrigation No Irrigation SavingsPlastic container 445 588 143Plastic container with SpinOut 445 784 339Air root-pruning (ARP) 445 672 227Low-profile ARP container 445 1,176 731Root-pruned, field-grown B&B 383 274 -109Non-root-pruned, field-grown B&B 383 383 0

Establishment: Seedling and Frequent Water

Spring 1998 Spring 1999

Advancements in Urban Forestry

From whip to chip

The Modern Use of Ash

Establishment: Weed whips, killing trees since 1972

Inventor George Ballas envisioned no damage to tree bark

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Not this

Establishment: Mulching Dosage and Spread

The more is not always the merrier

Or this

Establishment: Mulching

Dose and dispersal appropriate mulching

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atu

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C)

Mulch Affects Soil Moisture and Temperature

Moisture %

Establishment: Mulch and environmental conditions?

0

5

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15

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5

10

15

So

il M

ois

Te

mp

era

Treatment

Temperature (C)

(Iles and Dosmann ,1999 J. Arbor.)

Establishment: Trunk Protection

Formative Years: Formative Pruning, Select Best Leader

• Risk management

• Health

• Aesthetics

Formative Years: Why Prune Trees?

• Clearance

• What is your plan?

Are you doing something to or for the tree?

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Maturing: Which Limb to Remove? (Photos by Gary Johnson) Maturing: Now which limb to remove?

Included Bark

What will the tree look like, how will it respond?

Maturing: Cracks = separation of wood fibers Maturing: Codominants and Splitting?

Correctable? Shear Crack, Separation of Wood, Dangerous

Advancements in Urban Forestry

(Photos by Gary Johnson)

Maturing: Where to Prune

Hackberry and decay from included bark

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Maturing: Where to Prune

Location, minimize wound size, branch collar (Photos by Shigo)

Maturing: Subordination Pruning

Image by Edward F. Gilman (1997)

Maturing: Subordination Pruning 84% storm-damaged trees had pre-existing defects (Gary Johnson, UMN)

Tree Failure is Predictable and Preventable

Not the way to

Start the Day or

Infrastructure Risks to Arborists

Day, or End it for

that Matter

The End!