Using dendroecological techniques to interpret the response of trees to environmental change at the Vermont Monitoring Cooperative’s Mount Mansfield study.

Using dendroecological techniques to interpret the response of trees to environmental change at the

Vermont Monitoring Cooperative’s Mount Mansfield study site

Alexandra M. Kosiba1

Paul G. Schaberg2 Gary J. Hawley1

Shelly A. Rayback3

December 11th, 2014

1Rubenstein School of the Environment & Natural Resources, University of Vermont 2USDA Forest Service, Northern Research Station

3Dept. of Geography, University of Vermont

Observed changes in the region

• Growth declines, decreased vigor, increased mortality for some tree species in VT

• Red spruce • Sugar maple

• Other species appear to be stable• Possible growth increases

• Red spruce

• Anthropogenic stresses• Changes in climate• Acid deposition, land-use change

Project GoalAssess recent patterns and trends in growth for 5 key

forest tree species:

Sugar maple (Acer saccharum)

Red maple (Acer rubrum)

Yellow birch (Betula alleghaniensis)

Red spruce (Picea rubens)

Balsam fir (Abies balsamea)

Ranch Brook Watershed

Brown’s River Watershed

Stevensville Brook

Watershed

Map of Mt. Mansfield: sampling transects

Sampling scheme

Northern Hardwood Forest (< 760 m)

Transition Forest (760 – 880 m)

Boreal Forest (>880 m)

LOW ELEVATION

MIDELEVATION

HIGHELEVATION

Balsam fir

Red spruce

Red spruce

Red spruce

Sugar maple

Yellow birch

Sugar maple

Red maple

Methods

9 plots

3 elevations, 3 watersheds

12+ trees per species per plot (n trees = 265)

Standard dendrochronological techniques

Converted linear growth measurements area [BAI]

Standardized BAI (Z-score) Mean & SD for species/plot

Chronology: 1980-2012

1980 1985 1990 1995 2000 2005 2010-3

-2

-1

0

1

2

3

Sugar maple

Year

Z-s

core

Low elevation: comparison of standardized BAI

1980 1985 1990 1995 2000 2005 2010-3

-2

-1

0

1

2

3

Red maple Sugar maple

Year

Z-s

core

Low elevation: comparison of standardized BAI

1980 1985 1990 1995 2000 2005 2010-3

-2

-1

0

1

2

3

Red maple Red spruce Sugar maple

Year

Z-s

core

Low elevation: comparison of standardized BAI

1980 1985 1990 1995 2000 2005 2010-3

-2

-1

0

1

2

3

Sugar maple

Year

Z-s

core

Mid elevation: comparison of standardized BAI

1980 1985 1990 1995 2000 2005 2010-3

-2

-1

0

1

2

3

Sugar maple Yellow birch

Year

Z-s

core

Mid elevation: comparison of standardized BAI

1980 1985 1990 1995 2000 2005 2010-3

-2

-1

0

1

2

3

Sugar maple Red spruce Yellow birch

Year

Z-s

core

Mid elevation: comparison of standardized BAI

1980 1985 1990 1995 2000 2005 2010-3

-2

-1

0

1

2

3

Balsam fir

Year

Z-s

core

High elevation: comparison of standardized BAI

1980 1985 1990 1995 2000 2005 2010-3

-2

-1

0

1

2

3

Balsam fir Red spruce

Year

Z-s

core

High elevation: comparison of standardized BAI

Mean standardized basal area increment 2008-2012

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

Balsam fir Red maple Sugar maple Yellow birch Red spruce

Z-sc

ore

CC

AB

BC

A

* Different letters denote significant differences (ANOVA w/ Tukey-Kramer LSD, P < 0.05)

Red spruce chronology

1950 1960 1970 1980 1990 2000 20100

5

10

15

20

25

30

35

Region Mt. Mansfield

Mea

n B

AI (

cm2 )

Year

P < 0.0001, adjusted R2 = 0.84

Sugar maple chronologyM

ean

BA

I (cm

2 )

P < 0.0001 , adjusted R2 = 0.41

1950 1960 1970 1980 1990 2000 20100

5

10

15

20

25

30

35

Hubbard Brook Exp. Forest Mt. Mansfield

Year

HBEF data from C. Hansen (2014)

Yellow birch chronologyM

ean

BA

I (cm

2 )

P < 0.02, adjusted R2 = 0.077

1950 1960 1970 1980 1990 2000 20100

5

10

15

20

25

30

35

Hubbard Brook Exp. Forest Mt. Mansfield

Year

HBEF data from C. Hansen (2014)

Key findings

• Timing of max growth varied among the species:• Sugar maple + yellow birch = 1960s-80s• Red spruce + red maple = recent• Balsam fir = no peak

• Compared to species-specific means, in past 5 years…• Red spruce + red maple • Balsam fir + yellow birch • Sugar maple

• Red spruce had the highest growth that has occurred in the last 100 years region wide pattern

• Comparisons of growth at Mt. Mansfield similar to trends at other locations

Acknowledgements

Heather Bromberg, Ken Brown, Ben Engle, Kim Conway (USFS), Jim Duncan (VMC), Josh Halman,

Chris Hansen, Gary Hawley, Kindle Loomis, Allyson Makuch, Sam Wallace, Carl Waite (VMC)

Funding

Vermont Monitoring Cooperative

Questions?

Low elevation (<760m)

0

20

40

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30

Sugar maple

0

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40Red maple

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Red spruce

Bas

al a

rea

incr

emen

t (B

AI)

cm

2

N tr

ees

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Red spruce

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40Sugar maple

1895 1905 1915 1925 1935 1945 1955 1965 1975 1985 1995 20050

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Yellow birch

Mid elevation (760-880m)B

asal

are

a in

crem

ent (

BA

I) c

m2

N tr

ees

1895 1905 1915 1925 1935 1945 1955 1965 1975 1985 1995 2005 20150

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Red spruce

0

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40Balsam fir

High elevation (<880m)B

asal

are

a in

crem

ent (

BA

I) c

m2

N tr

ees

Year