- The study examined growth rates of sugar maple and yellow birch trees in a calcium-fertilized watershed (W1) versus an unfertilized reference watershed (W3) at Hubbard Brook Experimental Forest. - Tree cores were collected and ring widths measured, finding that sugar maple growth increased more in the fertilized watershed while the effect on yellow birch was unclear. - Statistical analysis found the difference in mean growth between the two watersheds was significant for both species. The results provide more details on the positive effects of calcium fertilization found in a previous study.

1. Next Steps
Acknowledgements
• Thank you, Matt Vadeboncoeur and Conor Madison for
their help in the tree core sampling, as well as Lauren
Buzinski for help throughout the study, especially for the
extraction of cellulose.
• Thank you for your generous help, time, and support, Matt
Vadeboncoeur and Heidi Asbjornsen.
• Thank you to the UNH Hamel Center for Undergraduate
Research for giving me this opportunity and funding.
.
Research Site
• Hubbard Brook Experimental Forest in
Woodstock, NH
• In October of 1999, powdered and pelletized
calcium was distributed via helicopter on W1 at
Hubbard Brook and increased the pH in the
organic layer of the soil (Battles et al. 2013).
• It is a secondary growth forest after the 19th and
20th –century logging, and it was exposed to the
1938 hurricane and an intense ice storm in
January 1998 (Battles et al. 2013).
MethodsIntroduction
Growth rate of calcium – fertilized sugar maple and yellow birch at Hubbard Brook
STACIE POWERS*, MATTHEW VADEBONCOEUR AND HEIDI ASBJORNSEN
NATURAL RESOURCES AND THE ENVIRONMENT, ENVIRONMENTAL CONSERVATION AND SUSTAINABILITY
UNIVERSITY OF NEW HAMPSHIRE, DURHAM, NH
*SLS78@WILDCATS.UNH.EDU
Conclusion
• Acid deposition and anthropogenic factors leach
calcium (Ca) from forest soils and mobilize toxic
aluminum (Al) in soils. Ca competes with Al for
uptake, leading to a calcium depletion and damage.
(USDA 2010)
• Calcium is an important macronutrient and has been
shown to be very important for certain tree species.
• Since the late 20th century, improved environmental
regulations, including the Clean Air Act, have
reduced acid deposition.
• I want to know if a watershed that was fertilized with
calcium showed a positive response with ring growth
and water efficiency when compared to a control
watershed (W3).
• It is important to understand the consequences of
acid deposition and to discover ways to restore
forests that have been affected by acid deposition.
Strategies such as forest fertilization may restore the
health of these ecosystems. (Battles et al. 2013)
0%
1%
2%
3%
4%
5%
1980 1985 1990 1995 2000 2005 2010 2015
relativebasalareaincrement
Year
Watershed 1
MEAN
UPPER CI
LOWER CI
Calcium
fertilization
0%
1%
2%
3%
4%
5%
6%
7%
8%
9%
10%
1980 1985 1990 1995 2000 2005 2010
Relativebasalareaincrement
Year
Cores collected in 2011 in Watershed 1
H1S1SM
H1S2SM
H1S4SM
H1S5SM
H1S6SM
H1S7SM
H1S8SM
H1S9SM
0%
1%
2%
3%
4%
5%
1980 1985 1990 1995 2000 2005 2010 2015
Relativebasalareaincrement
Year
Watershed 3 (reference)
MEAN
UPPER CI
LOWER CI
Ice storm of
1998
• Homogenize cellulose using the Branson
sonicator.
• Weigh cellulose samples for isotopic data on
evapotranspiration
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
1980 1985 1990 1995 2000 2005 2010
RADIALINCREMENT(MM)
YEAR
YELLOW BIRCH AVERAGE GROWTH
H3 Average H1 Average
• Calcium fertilization resulted in
growth in Sugar Maple and the
results of Yellow Birch is not
conclusive, however, it does
look like the fertilization had
much effect.
• This study adds more detail to
the past study by Battles et al.
2013.
• The t-test p value on the ratio of
both means from W1 and W3
(sugar maple and yellow birch)
is <.001.
• Collected sugar maple tree cores from Hubbard Brook in W3 and
W1 during the summer of 2014 and used pre-collected yellow
birch cores from 2011.
• Sanded the tree cores to make rings more visible and mounted
the cores onto wooden platforms.
• Counted and marked tree rings and then measured tree ring
width using Measure J2X and then cross-dated using COFECHA
• Found Basal Area Increments (BAI) for percent growth of each
year.
Calcium-
fertilized
watershed
Reference
watershed
Ice storm of
1998
Calcium
fertilizationIce
storm
of 1998
Calcium
fertilization
Ice
storm of
1998
Yellow Birch (In Progress)Sugar Maple
Figure. 1 The mean and confidence intervals of
all cores measured from watershed 3.
Figure. 2 The mean and confidence intervals of all cores
measured from watershed 1.
Figure. 3 An example of measured cores from
watershed 1.
0
0.5
1
1.5
2
2.5
3
3.5
4
1980 1985 1990 1995 2000 2005 2010
RADIALINCREMENT(MILLIMETERS)
YEAR
WATERSHED 3
H3YB1S4
H3YB2S4
H3YB2S5
H3YB2S7
H3YB2S8
H3YB3S2
H3YB3S4
H3YB3S7
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
1980 1985 1990 1995 2000 2005 2010
RADIALINCREMENTS(MILLIMETERS)
YEAR
WATERSHED 1
H1YB1S3
H1YB1S7
H1YB1S9
H1YB2S6
H1YB2S7
H1YB3S6
H1YB3S7
H1YB3S8
Figure. 4 Some measured tree cores from watershed 3
from 1980 to 2011.
Figure. 5 Some measured tree cores from watershed 1
from 1980 to 2011.
Figure. 6 The mean of all measured cores in watershed 1
and the mean of all measured cores in watershed 3 from
1980 to 2011.
2000
****************************************
*C* Number of dated series 28 *C*
*O* Master series 1914 2013 100 yrs *O*
*F* Total rings in all series 2254 *F*
*E* Total dated rings checked 2251 *E*
*C* Series intercorrelation .369 *C*
*H* Average mean sensitivity .267 *H*
*A* Segments, possible problems 91 *A*
*** Mean length of series 80.5 ***
****************************************
Seq Series Time_span 1905 1920 1935 1950 1965 1980 1995
1934 1949 1964 1979 1994 2009 2024
--- -------- --------- ---- ---- ---- ---- ---- ---- ----
1 H110SM1 1934 2013 -.16B-.18B-.18B-.08B .38A .48
2 13SM1 1947 2013 -.01B-.11B .11B .53 .52
3 H113SM2 1942 2013 .55 .58 .43 .55 .67
4 H1S14SM2 1919 2013 .03B-.03B .16A .20B .19B .37A .35A
5 H116SMT6 1924 2012 .00B-.07B-.07B .16B .63 .61
6 H117SM2 1949 2013 -.04B-.15B-.04B .43 .59
7 H118SM1 1940 2013 .45 .42A .63 .76 .74
8 H118SM2 1943 2013 .46 .32A .60 .73 .72
Av segment correlation .01 .19 .35 .36 .32 .48 .51
Sugar Maple is an important species for
its instrumental and monetary value and
acid deposition and calcium depletion is
one of the many reasons why it may not
be present in New England in the future.
The view while measuring tree rings using the
Measure J2X program
Results
A vial containing cellulose
after an extraction
A sugar maple tree core under a
light showing the tree rings.
Photos courtesy of Hubbard Brook Experimental Station website
Table 1. Correlations of individual tree cores
against a master chronology.
Table 2. COFECHA summary table with
calculated outputs and correlations.
The stereomicroscope and
Velmex platform used for
measuring.
Ice storm of
1998
Calcium
fertilization
Ice storm of
1998
Battles, John J., et al. “Restoring Soil Calcium Reverses Forest Decline.” Environmental Science and Technology
Letters vol. 1 (2014):15-19. Web. Sept 30 2014.
Driscoll, Charles, et al. “Acidic Deposition in the Northeastern United States: Sources and Inputs, Ecosystem Effects,
and Management Strategies.” Bioscience 51:3 (March, 2001): 180-198. Web. 30 Sept 2014.
Schaberg, Paul. "Acid Rain and Calcium Depletion." Forest Disturbance Processes. USDA Forest Service, 27 Jan.
2010. Web
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