1.
Background
• Hubbard Brook whole-watershed transpiration
response to wollastonite (CaSiO3) addition:
mechanisms unclear (Green et al. 2013)
• MELNHE wollastonite plots established in 2011
with aim to clarify
• Measuring sap flow is one method to estimate
transpiration (Granier, 1987)

2.
Background
• Preliminary sap flow measurements from HB Ca suggest
increased transpiration in wollastonite treatment (Zahor
et al. 2013)

3.
Research Question
• Does a wollastonite addition increase tree
transpiration?
• Expect that it does, possibly due to increased
xylem and fine root growth
• Alternatively, sap flow measurements could
reflect the transition to decreased transpiration
observed in W1 (Green et al. 2013)

4.
Methods
• Sap flow measured by the Granier method: reference probe 10 cm
below thermocouple heating probe with constant source of heat,
measures temperature difference (ΔT) (Granier, 1987)
• Measurements collected by data logger every 30 seconds, average
recorded every 15 minutes
• ΔT is converted to sapflux (Js, g x m2 x s-1) using BaseLiner
software (Oren and Parashkevov, 2012)
(Max Planck Institute for Biogeochemistry)

5.
Methods
• Sap flow to be measured in
wollastonite and control
plots at mature stands in
Bartlett Experimental Forest
(C8), Hubbard Brook
Experimental Forest (Ca)
and Jeffers Brook
• 9 canopy trees measured
per plot: 3 American beech,
3 sugar maple and 3 yellow
birch
• Measurements collected for
~5 days per stand

6.
Results
25
20
15
10
5
0
Bartlett C8
171.5 172 172.5 173 173.5 174 174.5 175 175.5 176 176.5 177
Sapflux (Js, g x m2 x s-1)
Ordinal Date and Time
C8 Control AB
C8 Control SM
C8 Control YB
C8 Ca AB
C8 Ca SM
C8 Ca YB

7.
Results
14
12
10
8
6
4
2
0
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM
Sapflux (Js, g x m2 x s-1)
C8 Yellow Birch 1 (CaSiO3)
YB1
• Example of a representative diurnal curve

8.
CaSiO3
Control
• Within species, more
variation across trees
than across
treatments
25
20
15
10
5
0
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM12:00 AM 4:48 AM
Sapflux (Js, g x m2 x s-1)
C8 American Beech
AB1
AB4
AB5
AB6
18
16
14
12
10
8
6
4
2
0
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM4:48 AM
Sapflux (Js, g x m2 x s-1)
C8 Sugar Maple
SM1
SM3
SM4
SM5
SM6
16
14
12
10
8
6
4
2
0
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM
Sapflux (Js, g x m2 x s-1)
C8 Yellow Birch
YB1
YB2
YB3
YB4
YB5
YB6

9.
60
50
40
30
20
10
0
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM4:48 AM
Sapflux (Js, g x m2 x s-1)
HB Sugar Maple
SM2
SM3
SM4
SM5
SM6
25
20
15
10
5
0
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM12:00 AM 4:48 AM
Sapflux (Js, g x m2 x s-1)
HB American Beech
AB1
AB3
AB4
AB5
AB6
25
20
15
10
5
0
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM
Sapflux (Js, g x m2 x s-1)
HB Yellow Birch
YB1
YB3
YB5
YB6
CaSiO3
Control
• Within species, more
variation across trees
than across
treatments

10.
Conclusion
• No apparent trends in sapflux between
treatments, individual trees highly
variable
• Solid dataset to work with that will help
direct future sap flow efforts

11.
Future Work
• Reevaluate methods: increase sample
size and consider additional factors in
analysis
• Take sap flow measurements from Jeffers
Brook, then return to Bartlett C8 and
Hubbard Brook for the remainder of the
field season
• Develop a statistical model to determine
significance

12.
References & Acknowledgements
• Granier, A. (1987). Evaluation of transpiration in a Douglas-fir stand by means of
sap flow measurements. Tree Physiology 3: 309-320.
• Green, M.B., et al. (2013). Decreased water flowing from a forest amended with
calcium silicate. Proceedings of the National Academy of Sciences
110(15):5999-6003.
• Oren, Parashkevov, & Duke University. (2012). BaseLiner (Version 2.4.2)
http://ch2oecology.env.duke.edu/orenlab/sofware.html
• Michele Pruyn
• Mariann Johnston
• Mark Green
• Ruth Yanai
• Adam Wild, our glorious leader
• Shoestring Crew