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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
0
10
20
30
Sugar maple
0
10
20
30
0
20
40Red maple
0
20
40
0
10
20
30
Red spruce
Bas
al a
rea
incr
emen
t (B
AI)
cm
2
N tr
ees
0
20
40
0
10
20
30
Red spruce
0
10
20
30
0
20
40Sugar maple
1895 1905 1915 1925 1935 1945 1955 1965 1975 1985 1995 20050
20
40
0
10
20
30
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
20
40
0
10
20
30
Red spruce
0
10
20
30
0
20
40Balsam fir
High elevation (<880m)B
asal
are
a in
crem
ent (
BA
I) c
m2
N tr
ees
Year