Evaluating Replacement Tree Species in Black Ash Forests

Threatened by EAB and Climate Change

The Context: millions of acres and billions of trees

The Concern: threatened by EAB and climate change

The Need: adaptive strategies, including replacement trees species

Brian Palik

USDA Forest Service

Northern Research

Station

Tony D’Amato

School of Environment

and Nat. Res., Univ. of

Vermont

Robert Slesak

Minnesota Forest

Resources

Council

Christopher

Looney Dept. of Nat. Res.,

Univ. of Minnesota

Mitch Slater

USDA Forest Service

Northern Research

Station

• Black ash forests are a large

proportion of Lake States

landbase

• 440,000 ha ( 1.1 million ac) & 1

billion trees in Minnesota

• Glacial lake and outwash plains,

muck soils, impeded drainage

Black Ash in Minnesota

Why black ash forests matter:

-Timber (Forest Industry)

-Habitat (Biodiversity)

-Carbon storage (Climate Change)

-Cultural resource (Basket Making)

NMS 1

-1.5 -1.0 -0.5 0.0 0.5 1.0

NM

S 3

-1.5

-1.0

-0.5

0.0

0.5

1.0

Mountain

MapleWhite

Cedar

Balsam

Poplar

Willow

Speckled

Alder

Red MapleQuaking

Aspen

Paper

Birch

Balsam

Fir

Choke

CherryYellow

Birch

Green Ash

American

Elm

Black

Ash

Species

Bla

ck a

sh

Bal

sam

fir

Bal

sam

popla

r

Pap

er b

irch

Am

eric

an e

lm

Gre

en a

sh

Quak

ing a

spen

Red

map

le

White

ced

ar

Yello

w b

irch

No

. p

er

ha

0

100

200

300

400

500

600

700 Overstory Species

Black ash can be the dominant species in wetland forests in the north

What do we know about black ash in Minnesota

Palik, Ostry, Venette, et al FEM 2011

What do we know about black ash stand structure?

-Long-lived trees (300+ years)

-Strongly uneven-aged; recruitment peaks reflective of drought and canopy disturbance

-Overstory present during regeneration events; gap-based dynamics

But Black Ash Forests have Issues…

Including…

Emerald Ash Borer

Emerald Ash Borer is on the

doorstep of the largest

concentration of ash in the

North America

More bad news… Climate projections for northern MN

Projected habitat changes for co-occurring

tree species in Fraxinus nigra wetlands:

-Reduced habitat suitability 50% of spp.

-Neutral: 25%

-Increased: 25%

Future adapted species occur

only in low abundance in these

forests

Species

Bla

ck ash

Bals

am fi

r

Bals

am p

oplar

Paper

birch

Am

erican e

lm

Gre

en ash

Quakin

g aspen

Red m

aple

White

cedar

Yello

w b

irch

No

. p

er

ha

0

100

200

300

400

500

600

700

EAB is cold sensitive; warmer

winters > EAB survival

Species

Bla

ck a

sh

Am

eric

an e

lm

Bal

sam

fir

Bal

sam

popla

r

Mounta

in m

aple

Quak

ing a

spen

Speckl

ed a

lder

Sugar m

aple

Will

ow

No

. p

er

ha

0

200

400

600

800

1000

Wetland

Upland

Sapling layer is

mostly black

ash and alder..

Also, few trees in

the regeneration

layer:

-speckled alder

-hazel

-mountain maple

-dogwood

Sapling Species

No tree species

poised to replace

black ash….should

something bad

happen!

Even more bad news… Not a lot of advance regeneration of other species

Palik, Ostry, Venette, et al FEM 2012

Without Trees…

-Black ash wetlands get even wetter

-Sedge/shrubs dominate

-Tree establishment becomes difficult

-Loss of ecosystem function, habitat

The Concern:

There is a growing sense of

urgency among regional

organizations to find adaptation

strategies to maintain trees in

these ecosystems

The Need:

Adaptive strategies, that keep

forests on the landscape

Including evaluation of replacement tree species

0 6030 Kilometers

Large-scale manipulative experiment on Chippewa National Forest

Evaluating the Ecological Impacts of

Emerald Ash Borer in Black Ash Forests

-What are potential impacts of EAB and

associated management actions on structure

and function of black ash forests?

-Are there adaptive strategies to build site-level

resilience to EAB and climate change (i.e.,

maintain forested wetland condition)?

Brian Palik

USDA Forest Service

Northern Research Station

Tony D’Amato

School of Environment and

Nat. Res., Univ. of Vermont

Robert Slesak

Minnesota Forest

Resources Council

10

Including evaluation of replacement tree species

-Conceived by Gary Swanson (CNF) in 2009

-Developed by Palik, D’Amato, Slesak in 2010

-Harvested winter 2011-12

-Planted 2011-2012

4 treatments

1. Unharvested control

2. Clearcutting

3. Group selection

4. EAB emulation

-All treatments are 1.6 ha (4 ac);

-8 replicates of each

Examining:

-Hydrology

-Native plant communities

-Natural regeneration

-Amphibian communities

-Aquatic food webs

-Planted regeneration growth & survival

Northern Wet Ash Swamp (WFn55);

Northern Very Wet Ash Swamp (WFn64)

The Study:

Group Selection

Clearcut

Girdling

Emulates EAB

Control

Treatments

Replacement Tree Species

-12 tree species: planted F2011 &/or Sp2012

-Most present in regional ecosystem:

Red Maple*, Yellow Birch*, Eastern Larch,

Eastern Cottonwood*, Black Spruce,

Balsam Poplar, Quaking Aspen, White

Cedar, American Elm*

-Two from the next southern climate zone:

Hackberry*, Swamp White Oak*

-One exotic:

Manchurian Ash*

Northeast Asia & Japan

EAB-resistant

*Future adapted: climate and EAB

Survival by species

• Survival highest for non-native,

pathologically-limited, or out-of-

range species

• Species with high survival are

predicted climate change adapted

• Survival lowest for commonly

occurring, native species

• Species with lowest survival are

often climate change mal-adapted

(predicted)

Percent survival (Year 5)

1. American elm (74)

2. Swamp white oak (69)

3. Manchurian ash (52)

4. Hackberry (43)

5. Balsam poplar (24)

6. Red maple (23)

7. Black spruce (11)

8. Tamarack (7)

9. White cedar (6)

10. Cottonwood (4)

11. Trembling aspen (3)

12. Yellow birch (3)

Results

Looney et al. CJFR 2015

Survival: Species x Planting Season

-Higher fall survival: swamp white oak, Manchurian ash, balsam poplar

-Higher spring survival: black spruce, red maple

-Generally not a large difference between planting seasons (overly wet microsites were avoided with spring planting)

Survival: Treatment x Species (5th year)

Mean Percent Survival (+/- 95% CI)

-Survival of future-adapted species was generally lower in the clearcut

-Similar patterns of survival among control, group, girdle

Looney et al. CJFR 2015

Planted Seedling Growth (2013 to 2015)

-Both height and diameter (relative) growth increased from the control to the group selection to the girdle treatment, to the clearcut

Results Looney et al. CJFR 2017

Growth parallels gradient in LAI

Growth: Treatment x Species

-Most species had highest growth in clearcut and girdle treatments, with group selection intermediate and control lowest

Relative Diameter Growth

Results

-Replacement species growth:

-Balsam poplar highest in all treatments;

-Swamp white oak and American elm moderate in all treatments,

-Manchurian ash and hackberry low in all treatments

Looney et al. CJFR 2017

Ranking replacement species:

-Need to balance survival and growth -Shorter and longer-term perspectives -Evaluated in the context of appropriate silvicultural approach

Rank order of 5th year

survival in group selection:

1. American elm (DED tolerant)

2. Swamp white oak

3. Manchurian ash

4. Hackberry

5. Balsam poplar

6. Red maple

7. Black spruce

8. Eastern larch

9. Northern white cedar

10.Eastern cottonwood

11.Yellow birch

12.Trembling aspen

Rank order of 3 year relative

diameter growth in group selection:

1. Balsam poplar

2. Eastern larch

3. Eastern cottonwood

4. Swamp white oak

5. Red maple

6. Black spruce

7. Northern white cedar

8. American elm (DED tolerant)

9. Hackberry

10.Manchurian ash

Trembling aspen, yellow birch: survival too

low to assess growth

Shorter term?

Longer term?

Recommended

replacement species

In rank order for northern wet

forests:

1. Tamarack

2. N. white cedar

3. American elm (DED tolerant)

4. Black spruce

5. Balsam poplar

6. Yellow birch

7. Balsam fir

8. Red maple

9. Trembling aspen

10.Ash

11.Silver maple

Replacements should consider:

-Site appropriateness,

-EAB resistance

-Future climate adaptation

(swamp white oak?)

?

Summary and Recommendations

• Adaptation strategies for black ash wetlands need to consider replacement tree

species, as well as the silvicultural approaches best suited to facilitate success

• Loss of trees from EAB or preemptive clearcutting, while increasing growth of some

species, shift sites towards challenging hydrologic conditions and may limit long-

term survival

• Group selection is consistent with the ecology of these systems (gap dynamics,

uneven-aged) and has generally good seedling survival, including several future

adapted species

• Balsam poplar and swamp white oak provide a good balance of growth and survival,

particular with group selection

• Fall planting may be logistically easier, has higher survival for some species, and

about the same survival as spring planting for most species

• Pre-emptive planting (before EAB) in uncut forest of tolerant, future-adapted species

may be a viable strategy

USDA Forest

Service Northern

Research Station