Shoestring2014 9-sapflow

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