shoestring2014 9-sapflow
DESCRIPTION
Does Wollastonite Make Trees More Thirsty? Measuring Sap Flow Sophie Harrison, Shoestring Crew 2014, University of MichiganTRANSCRIPT
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)
Background
• Preliminary sap flow measurements from HB Ca suggest increased transpiration in wollastonite treatment (Zahoret al. 2013)
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)
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 BaseLinersoftware (Oren and Parashkevov, 2012)
(Max Planck Institute for Biogeochemistry)
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
Results
0
5
10
15
20
25
171.5 172 172.5 173 173.5 174 174.5 175 175.5 176 176.5 177
Sap
flu
x (J
s, g
x m
2 x
s-1
)
Ordinal Date and Time
Bartlett C8
C8 Control AB
C8 Control SM
C8 Control YB
C8 Ca AB
C8 Ca SM
C8 Ca YB
Results
0
2
4
6
8
10
12
14
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM
Sap
flu
x (J
s, g
x m
2 x
s-1
)
C8 Yellow Birch 1 (CaSiO3)
YB1
• Example of a representative diurnal curve
• Within species, more variation across trees
than across treatments
CaSiO3
Control
0
5
10
15
20
25
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM
Sap
flu
x (J
s, g
x m
2 x
s-1
)
C8 American Beech
AB1
AB4
AB5
AB6
0
2
4
6
8
10
12
14
16
18
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM
Sap
flu
x (J
s, g
x m
2 x
s-1
)
C8 Sugar Maple
SM1
SM3
SM4
SM5
SM6
0
2
4
6
8
10
12
14
16
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM
Sap
flu
x (J
s, g
x m
2 x
s-1
)
C8 Yellow Birch
YB1
YB2
YB3
YB4
YB5
YB6
0
10
20
30
40
50
60
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM
Sap
flu
x (J
s, g
x m
2 x
s-1
)
HB Sugar Maple
SM2
SM3
SM4
SM5
SM6
0
5
10
15
20
25
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM
Sap
flu
x (J
s, g
x m
2 x
s-1
)
HB American Beech
AB1
AB3
AB4
AB5
AB6
0
5
10
15
20
25
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM
Sap
flu
x (J
s, g
x m
2 x
s-1
)
HB Yellow Birch
YB1
YB3
YB5
YB6
CaSiO3
Control
• Within species, more variation across trees
than across treatments
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
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
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 Sciences110(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